sweetwater creek - united states army creek...fema federal emergency management agency . fonsi...

SWEETWATER CREEK FLOOD RISK MANAGEMENT FEASIBILITY STUDY DRAFT INTEGRATED FEASIBILITY REPORT AND

ENVIRONMENTAL ASSESSMENT

APRIL 2018 Mobile District

Sweetwater Creek Flood Risk Management Study Draft Integrated Feasibility Report and Environmental Assessment April 2018

i

Table of Contents 1.0 Introduction ............................................................................................................... 1

1.1 Study Area ............................................................................................................. 1

1.2 Project Sponsor ..................................................................................................... 2

1.3 Purpose and Need ................................................................................................. 2

1.4 Study Authority ...................................................................................................... 3

1.5 Related Documents and Studies ........................................................................... 3

1.6 Other Projects in Study Area ................................................................................. 3

1.7 Tentatively Selected Plan and Evaluated Alternatives ........................................... 3

1.8 NEPA Considerations ............................................................................................ 3

2.0 Existing and Future Without-Project Conditions (No Action Alternative) ................... 4

2.1 Topography, Geology, and Soils............................................................................ 4

Existing............................................................................................................ 4

FWOP ............................................................................................................. 4

2.2 Air Quality and greenhouse gases ......................................................................... 1

Existing............................................................................................................ 1

FWOP ............................................................................................................. 1

2.3 Land Use ............................................................................................................... 1

Existing............................................................................................................ 1

FWOP ............................................................................................................. 1

2.4 Water Resources ................................................................................................... 3

Sweetwater Creek and Tributaries .................................................................. 3

Surface Water quality ...................................................................................... 4

Groundwater ................................................................................................... 6

2.5 Biological Resources ............................................................................................. 7

Vegetation ....................................................................................................... 7

Fish and Wildlife Resources ............................................................................ 9

Waters of the U.S. including Wetlands ............................................................ 9

Special Status Species ................................................................................. 12

Wildlife Corridors ........................................................................................... 13

2.6 Cultural Resources .............................................................................................. 14

Existing.......................................................................................................... 14

FWOP ........................................................................................................... 20

2.7 Sociological Resources ....................................................................................... 20

Flooding and Flood Damages ....................................................................... 20


ii

Hazardous Toxic Radiological Waste ............................................................ 24

Noise ............................................................................................................. 25

Aesthetic ....................................................................................................... 25

Navigation ..................................................................................................... 26

Socioeconomics ............................................................................................ 26

Public Safety ................................................................................................. 28

Recreation ..................................................................................................... 28

3.0 Plan Formulation ..................................................................................................... 28

Problems ....................................................................................................... 28

Opportunities ................................................................................................. 29

Objectives ..................................................................................................... 29

Constraints .................................................................................................... 29

3.2 Management Measures ....................................................................................... 29

Screening of General Measures .................................................................... 30

3.3 Site Specific Measures and Screening ................................................................ 31

Channel Modification ..................................................................................... 31

Diversion ....................................................................................................... 31

Retention Areas ............................................................................................ 32

Structure Relocation/Evacuation (buyout) ..................................................... 33

Flood Warning System .................................................................................. 33

3.4 Final Array of Alternatives .................................................................................... 34

Alternative 1: Relocation/Evacuation of Structures (Buy Outs) ..................... 34

Alternative 2: Brown Road Detention Alternative .......................................... 34

Alternative 4: Austell Channel Modification ................................................... 34

Alternative 5H: Multiple Detention Structures on Sweetwater Creek ............. 35

Alternative 5D: Multi-Subbasin Detention ...................................................... 35

Alternative 5J: South Paulding High Detention Short ................................... 36

Final Alternative Array Summary ................................................................... 36

3.5 Comparison of Final Alternatives ......................................................................... 38

Completeness ............................................................................................... 39

Effectiveness ................................................................................................. 39

Acceptability .................................................................................................. 41

Efficiency ....................................................................................................... 41

3.6 Plan Selection ...................................................................................................... 43


iii

4.0 Tentatively Selected Plan ........................................................................................ 43

4.1 Sites required and Area of Effect ......................................................................... 43

4.2 Cost ..................................................................................................................... 44

5.0 Environmental Impacts of the Tentatively Selected Plan ......................................... 44

5.1 Topography, Geology, and Soils.......................................................................... 46

5.2 Air Quality and Greenhouse Gases ..................................................................... 46

5.3 Land Use ............................................................................................................. 47

5.4 Water Resources ................................................................................................. 47

Sweetwater Creek and Tributaries ................................................................ 47

Surface Water quality .................................................................................... 47

Groundwater ................................................................................................. 49

5.5 Biological Resources ........................................................................................... 49

Vegetation ..................................................................................................... 49

Fish and Wildlife Resources .......................................................................... 49

Waters of the U.S. including Wetlands .......................................................... 49

Special Status Species ................................................................................. 49

Wildlife Corridors ........................................................................................... 50

5.6 Cultural Resources .............................................................................................. 50

Cultural Resource Identification .................................................................... 50

5.7 Sociological Resources ....................................................................................... 50

Flooding and Flood Damages ....................................................................... 50

Hazardous Toxic Radiological Waste ............................................................ 51

Noise ............................................................................................................. 52

Aesthetic ....................................................................................................... 52

Navigation ..................................................................................................... 53

Socioeconomics ............................................................................................ 53

Public Safety ................................................................................................. 53

Recreation ..................................................................................................... 53

6.0 Environmental Compliance ..................................................................................... 53

6.1 Coordination ........................................................................................................ 55

Fish and Wildlife Coordination Act ................................................................ 56

7.0 References .............................................................................................................. 56


iv

List of Tables Table 1: Future Structure Counts ................................................................................... 3 Table 2: 2014 303d Listed Waters .................................................................................. 4 Table 3: Federally Listed Species – Cobb, Douglas, Paulding Counties ....................... 12 Table 4: NRHP listed properties within the study area. ................................................ 16 Table 5: Previously Recorded Archaeological Sites within in a mile radius of all Alternatives. .................................................................................................................. 16 Table 6: Previously Recorded Archaeological Sites within in a mile radius of the proposed parcel locations for the Recommended Plan. ................................................ 20 Table 7: Total Depreciated Replacement Value of Study Area ..................................... 21 Table 8: Existing Condition Mean Expected Annual Damages (x 1,000, 2017 Prices) . 22 Table 9: Existing vs. Future Mean Expected Annual Damages (x 1,000, 2017 Prices) . 24 Table 10: Study Area Demographics............................................................................ 26 Table 11: Study Area Housing ..................................................................................... 26 Table 12: Study Area Income ....................................................................................... 27 Table 13: Study Area Occupation ................................................................................ 27 Table 14: Study Area Industry ...................................................................................... 27 Table 15: Measures Considered ................................................................................... 30 Table 16: Structures for Purchase by Annual Chance of Exceedance .......................... 34 Table 17: Measures in Final Array Summary ................................................................ 37 Table 18: Measures in Alternatives ............................................................................... 37 Table 19: Alternatives Equivalent Annual Damages Reduced(x1000, 2017 Prices) ..... 39 Table 20: Reduce Number of Structures Impacted ....................................................... 40 Table 21: Reduced Response Times Qualitative Summary .......................................... 40 Table 22: Reduced Response Times Qualitative Summary .......................................... 41 Table 23: Alternative Project Costs .............................................................................. 41 Table 24: Cost and Benefit Comparison ........................................................................ 42 Table 25: Benefit Uncertainty Analysis .......................................................................... 42 Table 26: Number of Structure in Tentatively Selected Plan by Reach ........................ 44 Table 27: Tentatively Selected Plan Parcel IDs ........................................................... 44 Table 28: Environmental Impacts Summary ................................................................. 46 Table 29: Tentatively Selected Plan Identified Properties and Nearby USEPA 303(d) Listed Waterbodies........................................................................................................ 48 Table 30: Tentatively Selected Plan Identified Properties and Likelihood of Nearby State Waters ................................................................................................................. 48 Table 31: TSP Identified Properties and Age of Structures .......................................... 51 Table 32: Public Law Environmental Compliance Status ............................................. 54 Table 33: Coordination ................................................................................................. 56


v

List of Figures Figure 1: Study Area ....................................................................................................... 1 Figure 2: USGS Sweetwater below Austell, Georgia historic river crests ........................ 2 Figure 3: USEPA Level IV Ecoregions of the continental U.S. ....................................... 1 Figure 4: Sweetwater Creek Watershed National Land Cover Database Overview ....... 2 Figure 5: USEPA Listed Impaired Waters within the Study Area ................................... 5 Figure 6: Approximate Location of Sweetwater Creek Watershed within USFS Ecoregions of the U.S. .................................................................................................... 8 Figure 7: Sweetwater Creek Watershed Wetland Types .............................................. 11 Figure 8: Location Map of Previously Recorded Archaeological Sites and NRHP Listed Properties within in a mile radius of all project alternative work sites. ........................... 18 Figure 9: Location Map of Previously Recorded Archaeological Sites within in a mile radius of all proposed buyout locations. ........................................................................ 19 Figure 10: 2% Annual Chance of Exceedance Floodplain Extents .............................. 23 Figure 11: Channel Modification and Diversion Measures ............................................ 32 Figure 12: Possible Retention Sites .............................................................................. 33 Figure 13: Measures in Final Array ............................................................................... 38 Figure 14: 1st and 3rd Quartile Uncertainty for Economically Justified Alternatives ........ 43 Figure 15: Tentatively Selected Plan ............................................................................ 45

Appendices Appendix A: Economics Appendix B: Engineering Appendix C: Cost Estimation Appendix D: Real Estate Appendix E: Environmental Appendix F: Federal and State Agency Coordination Appendix G: Public and Agency Comments


vi

Acronyms

ACE Annual Chance of Exceedance BGEPA Bald and Golden Eagle Protection Act BMPs Best Management Practices CAA Clean Air Act CWA Clean Water Act ESA Endangered Species Act FEMA Federal Emergency Management Agency FONSI Finding of No Significant Impact FRM Flood Risk Management FWCA Fish and Wildlife Coordination Act FWOP Future Without Project GEPD Georgia Environmental Protection Division GIS Geographic Information System GNAHRGIS Georgia’s Natural, Archaeological, and Historic Resources GIS HEC-FDA Hydrologic Engineering Center Flood Damage Reduction Analysis HEC-RAS Hydrologic Engineering Center River Analysis System HTRW Hazardous, Toxic, and Radiological Waste MBTA Migratory Bird Treaty Act NAAQS National Ambient Air Quality Standards NED Net Economic Development NEPA National Environmental Policy Act NFS Non-Federal Sponsor NHPA National Historic Preservation Act NLCD National Land Cover Database NPDES National Pollutant Discharge Elimination System NRHP National Register of Historic Places OSHA Occupational Safety and Health Administration RECs Recognized Environmental Conditions SHPO State Historic Preservation Officer T & E Threatened and/or endangered TMDL Total Maximum Daily Loads TSP Tentatively Selected Plan USEPA U.S. Environmental Protection Agency USFS U.S. Forest Service USFWS U.S. Fish and Wildlife Service USGS U.S. Geological Survey


1

1.0 Introduction

1.1 Study Area The Sweetwater Creek Watershed (Figure 1) encompasses 264 square miles in Paulding, Douglas, and Cobb Counties in Georgia. The main stem of Sweetwater Creek is 45.6 miles long and begins in Paulding County. As it flows eastward towards Cobb County other tributaries join the main stem before it empties into the Chattahoochee River in Douglas County at the Fulton County line. The creek passes through Sweetwater Creek State Park just before its confluence with the Chattahoochee River.

Figure 1: Study Area

The study area encompasses the entire Sweetwater Creek Watershed. The watershed is a mixed watershed that is mostly rural with multiple developed urban areas. The rural areas make up most of the headwaters and it becomes more urban the closer to Sweetwater Creek State Park in the southeastern portion of the watershed. The majority of the urban areas and flood risk are within Cobb County, Georgia. The portion within Cobb County, Georgia is the intended area of flood risk improvement. The Cobb County portion includes the cities of Marietta, Austell, and Powder Springs as well as a portion of unincorporated Cobb County, Georgia. Located inside the study area are 14 public schools, 7 senior care facilities, and 1 hospital. The City of Hiram, City of Douglasville, and community of Lithia Springs are within the study area.


2

1.2 Project Sponsor Cobb County, Georgia is the Non-Federal Sponsor (NFS) for the Sweetwater Creek Flood Risk Management (FRM) Study.

1.3 Purpose and Need The purpose of the study is to investigate the Federal interest and feasibility of a FRM project to address flooding in the Sweetwater Creek Watershed specifically, inside Cobb County, Georgia. The historic recorded crests of the U.S. Geological Survey (USGS) gauge on Sweetwater Creek below Austell, Georgia, from 1937 to 2015 are shown below. Major floods are17 foot or greater crest, while moderate floods 13 to 17, and minor floods have10 to 13 foot crest. The highest recorded crest is 30.82 feet, which occurred in September 2009, and had a stream flow of 31,500 cubic feet per second.

Figure 2: USGS Sweetwater below Austell, Georgia historic river crests

In September 2009, catastrophic flooding impacted the Atlanta metropolitan area as a result of multiple days of prolonged rainfall. According to the rain gauge at Douglas County Water and Sewer Authority the maximum 24-hour rainfall total for September 20-21 was 21.03 inches, which represents a 0.01% annual chance of exceedance (ACE). Historic flash flooding resulted, with flooded river basins remaining swollen for weeks which resulted in numerous flood records were set. Some locations observed conditions exceeding the 0.2% chance of occurrence in a given year. Two of the public schools in the City of Austell flooded or were surrounded by water and one was flooded to the roof line.

0

4

8

12

16

20

24

28

32

Rive

r Cre

st (f

eet)

Year

Flood Height Minor Flood Moderate Flood Major Flood


3

1.4 Study Authority The project is authorized by House Resolution 2445 of the Committee on Public Works and Transportation of the United States House of Representatives adopted 28 September 1994 which reads:

…the interest of environmental quality, water quality, water supply, flood damage reduction, and other purposes including a comprehensive, coordinated watershed master plan for metropolitan Atlanta, Georgia. Such studies should address water quality and flooding associated with stormwater runoff in Nancy Creek, Utoy Creek, North Peachtree Creek, South Peachtree Creek, and other Watersheds in the Fulton, and DeKalb County area, including identification and evaluation of environmental infrastructure and resource protection needs; flood control needs of the Flint River Basin; and water supply needs of the northwest Georgia area.

The above authority pertains to the area that is part of the master plan for metropolitan Atlanta, Georgia. The study area is mostly in Cobb and Douglas Counties, Georgia which are part of the 10 counties that make up the Metropolitan Atlanta Master Plan, as set forth by the Atlanta Regional Commission. Further, any FRM effects would directly or indirectly impact a portion of one or both of these counties. This study is an interim response to the authority since it only addresses the FRM in the Sweetwater Creek Basin and does assess FRM in other portions of the metropolitan Atlanta area.

1.5 Related Documents and Studies The Flood-Inundation Maps for Sweetwater Creek from Above the Confluence of Powder Springs Creek to the Interstate 20 Bridge, Cobb and Douglas counties, Georgia prepared by Cobb county with the U.S. Department of the Interior and U.S. Geological Survey (USGS) documented the extents of the September 2009 flood.

1.6 Other Projects in Study Area In the last 3 years the Federal Emergency Management Agency (FEMA) flood maps for the three counties that comprise the Sweetwater Creek basin have been updated. A Georgia Silver Jackets study created a real-time flood inundation map for the cities of Austell and Powder Springs.

1.7 Tentatively Selected Plan and Evaluated Alternatives The Tentatively Selected Plan (TSP) is to implement a relocation of the structures effected by the 10% ACE event. Other alternatives that were evaluated were dry retention sites, channel widening and deepening, bridge modification, levees, raising buildings, and channel diversions. More information on the evaluation of the alternatives is contained in Section 3.0 Plan Formulation.

1.8 NEPA Considerations Environmental conditions evaluated during the FRM study included water, biological, and cultural resources. Resources of concern in relation to this study centered on water quality, federally protected species, and cultural resources. See Section 2.0 Existing


4

and Future Without-Project Conditions (No Action Alternative) and Section 5.0 Environmental Impacts of the for an in-depth analysis. 2.0 Existing and Future Without-Project Conditions (No Action Alternative)

The existing condition is a baseline from which all of the future conditions are based. The future without project condition (FWOP) is the anticipated future for a given resource if no action is taken or implemented. Details on both the existing and FWOP condition are detailed in the following sections.

2.1 Topography, Geology, and Soils Existing

Topography Since 1987 the U.S. Environmental Protection Agency (USEPA) has defined ecoregions throughout the conterminous United States for the use of classifying habitat ecosystems based on physiological characteristics such as varying topography, geology, and soils (Omernik 1987). As shown in Figure 3: USEPA Level IV Ecoregions of the continental U.S., Sweetwater Creek Watershed lies within the Southern Inner Piedmont portion of the Piedmont Ecoregion of the State of Georgia. The Piedmont Ecoregion is considered non-mountainous foothills of the Appalachian Mountain Range and transitions to the relatively flat coastal plain in the direction of northeast to southwest. It is comprised of numerous shallow streams, granite outcrops, flat to rolling terrain, and narrow valleys. Geology Sweetwater Creek Watershed is a tributary to the Chattahoochee River which runs parallel to the Brevard Fault Zone which a prominent geologic feature of the Southeast United States formed through seismic activity (Vauchez 1987). Bedrock in the USEPA defined Piedmont Ecoregion consists of Precambrian and Paleozoic metamorphic and igneous rocks such as granite, gneiss, and marble (GWRD 2001). Soils Soils of the USEPA defined Piedmont Ecoregion are comprised of fine grained saprolites and ultisols which are chemically weathered rocks and leached acidic sandy or loams soils respectively. Ultisols of the Piedmont Ecoregion range in color from bright red or reddish-yellow to orange or pale yellow-brown. Due to 19th century farming practices, topsoil erosion has led to the exposure of these soils which were formed through the weathering of igneous and metamorphic bedrock.

FWOP No changes to topography would occur under future without project conditions.


1

Figure 3: USEPA Level IV Ecoregions of the continental U.S.


1

2.2 Air Quality and greenhouse gases Existing

The USEPA sets National Ambient Air Quality Standards (NAAQS) in accordance with the Clean Air Act (CAA) “for pollutants considered harmful to public health and the environment.” The Clean Air Act identifies two types of NAAQS: primary and secondary. Primary standards provide public health protection and Secondary standards provide public welfare protection. The USEPA has set NAAQS for six principal pollutants, which are called criteria air pollutants: carbon monoxide, nitrogen dioxide, ozone, sulfur dioxide, lead, and particulate matter (PM10 and PM25). The General Conformity Rule published by the USEPA on November 30, 1993 designates and implements Section 176(c) of the CAA for geographic areas in CAA non-attainment areas for criteria pollutants and in those attainment areas subject to maintenance plans required by CAA Section 175(a). The CAA General Conformity Rule applies to Federal actions. The study area is not located in any designated nonattainment areas for any criteria air pollutants.

FWOP Local air quality would continue fluctuating trends but overall would remain consistent with current levels.

2.3 Land Use Existing

In June 2017, parcels within the 500 year floodplain for Sweetwater Creek and its tributaries within Cobb, Douglas and Paulding Counties were surveyed for use in a FRM study. Parcel data was obtained by each county’s tax assessor’s office and used to build a geographic information system (GIS) database for identifying which parcels were located within the FEMA 500 year floodplain. The structure inventory survey identified 2,230 structures within 1,902 parcels not including vacant lots. More details on the structure inventory and how it was used can be found in Appendix A: Economics The setting of the Sweetwater Creek study area is mostly rural and suburban with small cities such as Austell and Powder Springs, which have developed near the floodplains of Sweetwater Creek and Powder Springs Creek respectively. Data obtained from the Multi-Resolution Land Characteristics Consortium 2011 National Land Cover Database (NLCD), depicted in Figure 4: Sweetwater Creek Watershed National Land Cover Database Overview, provides a visual representation of the land use overview throughout the entire study area.

FWOP According to Georgia residential population projections, the population of the counties within the study area (Cobb, Douglas and Paulding) are expected to increase by approximately 34.89% by the year 2050.


2

Figure 4: Sweetwater Creek Watershed National Land Cover Database Overview


3

The average household size in the state of Georgia is 2.73 persons. Dividing the percent increase by 2.73 households estimates the expected increase in households in the year 2050 is 12.78%. This is represented by the addition of 213 residential structures in the 2050 analysis year, located above of the 1% ACE exceedance event floodplain. These structures were added to the year 2050 structure inventory in proportion to the number of structures within each reach. The number of structures for Table 1: Future Structure Counts differs from overall structure count due to counting multi-structure parcels as one, resulting in a difference of 286. It is assumed that by the year 2050 the floodplain will be fully developed and no future development will occur.

Table 1: Future Structure Counts

Reach Analysis Year

2020 Number of Structures

Percent of Residential Structures

Future Structures

Added

Analysis Year 2070 number of structures

Buttermilk 46 2.75% 6 52 Mill 62 3.71% 8 70

Noses 589 35.2% 75 664 Olley 116 6.93% 15 131

Powder Springs 189 11.30% 24 213 Sweetwater 671 40.11% 85 756

Total: 1,673 100% 213 1,886

2.4 Water Resources Sweetwater Creek and Tributaries

Existing The Sweetwater Creek watershed encompasses 264 square miles in Paulding, Douglas, and Cobb Counties in Georgia. The main stem of Sweetwater Creek is 45.6 miles long and begins in Paulding County. As it flows eastward towards Cobb County, other tributaries join the main stem before it empties into the Chattahoochee River in Douglas County at the Fulton County line. The creek passes through Sweetwater Creek State Park just before its confluence with the Chattahoochee River. The Study Area encompasses the entire Sweetwater Creek watershed; however, the portion within Cobb County, Georgia is the intended area of flood risk improvement. The Cobb County portion includes the cities of Marietta, Austell and Powder Springs as well as a portion of unincorporated Cobb County, Georgia. Buttermilk Creek, Mill Creek, Noses Creek, Olley Creek, and Powder Springs Creek are all tributaries of Sweetwater Creek and are predominantly located in Cobb County, Georgia. See Figure 1: Study Area for the location of each tributary.

FWOP Flooding within the study area would increase at a rate of less than 1% for the 1% ACE flood event in the FWOP conditions.


4

Surface Water quality Existing

Section 401 of the Clean Water Act (CWA) prohibits the discharge of any fill material into navigable waters of the United States. The USEPA delegates authority under this act to the States for monitoring and maintaining clean water standards. Every two years the USEPA will review and approve the State’s listing of impaired or threatened bodies of water (e.g. stream/river segments, lakes), termed 303(d) list. States are required to submit their list for USEPA approval every two years. For each waterbody on the list, the state identifies the pollutant causing the impairment, when known. In addition, the state assigns a priority for development of Total Maximum Daily Loads (TMDL) based on the severity of the pollution and the sensitivity of the uses to be made of the waters, among other factors (40 C.F.R. §130.7(b)(4)).” The nearest 303d listed bodies of water within or near the study area are Buttermilk Creek, Olley Creek, and a portion of Sweetwater Creek. Those reaches identified within Buttermilk and Olley Creek located in the headwaters to Sweetwater Creek in Cobb County. All locations are listed as not supporting its designated use either due to Fecal Coliform Bacteria, Urban Runoff/Urban Effects, and/or Biota Impacted Fish or Macroinvertebrate Community. See Table 2 and Figure 5 for listed streams not supporting designated uses within the study area obtained from the Georgia Department of Natural Resources, Environmental Protection Division (GEPD) 2014 303d listed waters for streams and rivers.

Table 2: 2014 303d Listed Waters Reach Name/ID Reach Location /

County Use Cause / Source Size

Buttermilk Creek / R031300020209 Headwaters to Sweetwater Creek / Cobb

Fishing FC/UR 4 miles

Olley Creek/ R031300020204 Headwaters to Sweetwater Creek / Cobb

Fishing Bio M, FC/UR

11 miles

Sweetwater Creek / R031300020217 Unnamed Tributary approximately 0.25 miles u/s of I-20 to the Chattahoochee River / Douglas

Fishing FC/UR 8 miles

Tributary to Mud Creek/ R031300020207

Cobb County / Cobb Fishing FC/UR 3 miles

Mud Creek / R031300020202

Ga. Hwy. 120 to Noses Creek / Cobb Fishing FC/UR 5 miles

Noses Creek / R031300020215 Headwaters to Ward Creek / Cobb Fishing Bio F /

NP 7 miles

Ward Creek / R031300020208 Headwaters to Noses Creek / Cobb Fishing FC, Bio F

/ UR 6 miles

Cracker Creek / R031300020210 Headwaters to Gothard's Creek / Douglas Fishing FC/UR 3 miles

Key 2: Bio M = Biota Impacted (Macroinvertebrate Community); Bio F = Biota Impacted (Fish Community); FC = Fecal Coliform Bacteria ; NP = Nonpoint Sources/Unknown Sources; UR = Urban Runoff/Urban Effects


5

Figure 5: USEPA Listed Impaired Waters within the Study Area


6

Cobb County Water System maintains a stream monitoring program which evaluates chemical conditions, fish and macroinvertebrate diversity, as well as geomorphology to determine habitat quality. The county has collected this data for over 30 years. Recent data collections obtained from Cobb County Water System and personnel communications are included in Appendix E. The USEPA requires that “State waters” are maintained and regulated by State governments for the protection and conservation of land and water resources through the use of riparian/stream buffer zones. These buffer zones have been shown to reduce nitrogen leaching into groundwaters and streams (Mayer et. al 2005). The GEPD Field Guide for Determining the Presence of State Waters That Require a Buffer defines “State waters” as

Any and all rivers, streams, creeks, branches, lakes, reservoirs, ponds, drainage systems, springs, wells, and other bodies of surface or subsurface water, natural and artificial, lying within or forming a part of the boundaries of the State which are not entirely confined and retained completely upon the property of a single individual, partnership, or corporation, except as may be defined in O.C.G.A. 12-7-17(8) (O.C.G.A. 12-7-3(16).

For warm water streams a buffer zone of 25 feet must be maintained. For trout streams a 50 foot buffer zone must be maintained. Stream buffer zones are measured from the point of “wrested vegetation” based on stream type. “Wrested vegetation” is defined as: “the point at which visible demarcation between vegetation and water flow”. No extensive surveys have been completed to identify stream characteristics within the study area.

FWOP FWOP conditions show an increase of less than 1% increase in flooding for the 1% ACE flood event. Continued localized flooding would lead to decreased water quality, as sediments and debris runoff enter waters.

Groundwater Existing

Groundwater recharge potential within the Piedmont region, in which the Sweetwater Creek Watershed lies, is low due to the geology of the region. Sporadic groundwater sources in the crystalline rocks of the Piedmont Physiographic Province inhibits the use of groundwater as a major water supply (USGS 2017). However, the GEPD Watershed Protection Branch is evaluating the potential to supplement water supply sources in this region by using groundwater (GEPD 2017). Additionally, the USGS is studying how regional water availability is affected by water withdrawals in areas where ground water resources exist.

FWOP Groundwater supply would remain consistent with existing levels under the future without project conditions.


7

2.5 Biological Resources Vegetation

Existing The U.S. Forest Service (USFS) has defined ecological regions of the United States through a hierarchal assessment of domains, divisions, and provinces. Based on the USFS Ecoregion Map provided in Figure 6: Approximate Location of Sweetwater Creek Watershed within USFS Ecoregions of the U.S. , the study area lies within the south eastern mixed forest province of the continental United States (Bailey 1995). Since extensive cultivation practices during the 19th century, much of the Piedmont Ecoregion has reverted to pine and hardwood woodlands. Vegetation within the Southern Mixed Forest Province ranges from medium to tall forests of broadleaf deciduous trees and evergreen pine trees (Bailey 1995). Existing habitat within the study area ranges from heavily disturbed areas to forested riparian settings. Dominant native plant species throughout the study area include tulip poplar (Liriodendron tulipifera),, white oak (Quercus alba), northern red oak (Q. rubra), black oak (Q. velutina), post oak (Q. stellata), hickories (Carya glabra, C. tomentosa, and C. cordiformis), American beech (Fagus grandifolia), loblolly pine (Pinus taeda), Virginia pine (Pinus virginiana), sweetgum (Liquidambar styraciflua), black cherry (Prunus serotina), flowering dogwood (Cornus florida), box elder (Acer negundo), and eastern red cedar (Juniperus virginiana). Invasive plant species include greenbriar (Smilax spp.), Chinese privet (Ligustrum sinense), Japanese honeysuckle (Lonicera japonica), and tall goldenrod (Solidago altissima). Invasive plant species throughout the area include Japanese arrowroot (Pueraria montana var. lobata), cogongrass (Imperata cylindrical), yellow iris (Iris pseudacorus), Japanese honeysuckle (Lonicera japonica), star-of-Bethlehem (Ornithogalum umbellatum), garlic mustard (Alliaria petiolate), and Chinese wisteria (Wisteria sinensis). Cobb County currently operates a lawn care maintenance plan through frequent property mowing which prevents the growth of invasive plant species. No formalized invasive species control plans exist within the study area.

FWOP Existing vegetation in the study area would be subject to local municipality land use. However should no development occur vegetation would experience a less than 1% increase of flooding within the 1% ACE storm event, which could have the potential to disrupt the existing balance of the riparian habitat. Increased flooding has been shown to alter plant biomass as a result of a change in soil chemical composition and transportation of seeds throughout the riparian zone (Garssen et. al 2017). Consequently, the potential for an increased transport of invasive plant species throughout the area would exist under the FWOP.

Sweetwater Creek Flood Risk Management Study Integrated Feasibility Report and Environmental Assessment March 2018

8

Figure 6: Approximate Location of Sweetwater Creek Watershed within USFS Ecoregions of

the U.S.


9

Fish and Wildlife Resources Existing

Wildlife species vary throughout the Southern Mixed Forest Province. Their presence depends on age and thickness of timber stands, percent of deciduous trees, proximity to clearings, and bottom-land forest types (Bailey 1995). The habitat in the study area is diverse as it passes through undeveloped portions of Cobb, Douglas, and Paulding Counties to sparsely rural residential areas and more developed or urbanized territories. The variety of species found within portions of the study area are dependent on the level of development. More developed areas, such as the City of Austell contain species that are tolerate of human development activities. Conversely, undeveloped portions of the study area such as unincorporated Cobb County and the Sweetwater Creek State Park, contain habitat supporting a wider variety of wildlife. Common species found throughout the study area include white-tailed deer (Odocoileus virginianus), eastern wild turkey (Meleagris gallopavo silvestris), cottontail rabbit (Sylvilagus spp.), raccoon (Procyon lotor), nine-banded armadillo (Dasypus novemcinctus), bats (Chiroptera spp.), opossum (Didelphis virginiana), red fox, (Vulpes vulpes), fox squirrel (Sciurus niger), gray squirrel (Sciurus carolinensis), river otter (Lontra canadensis), mourning dove (Zenaida macroura), blue jay (Cyanocitta cristata), cardinal (Cardinalidae spp.), summer tanager (Piranga rubra), American crow (Corvus brachyrhynchos), mockingbird (Mimus polyglotus), starling (Sturnus vulgaris), Carolina wren (Thryothorus ludovicianus), ruby-throated hummingbird (Archilochus colubris), osprey (Pandion haliaetus), pine warbler (Setophaga pinus), eastern bluebird (Sialia sialis), hooded warbler (Setophaga citrina), northern bobwhite (Colinus virginianus), wood thrush (Hylocichla mustelina), eastern towhee (Pipilo erythrophthalmus), osprey (Pandion haliaetus), tufted titmouse (Baeolophus bicolor), cottonmouth moccasin (Agkistrodon piscivorus),copperhead (Agkistrodon contortrix), rough green snake (Opheodrys aestivus), coachwhip (Masticophis flagellum), speckled kingsnake (Lampropeltis getula holbrooki), eastern fence lizard (Sceloporus undulatus), glass lizard (Ophisaurus spp.), northern slimy salamander (Plethodon glutinosus), and gopher frog (Rana capito). Invasive wildlife species throughout the area include starling (Sturnus vulgaris), Africanized honeybee (Apis mellifera scutellata), wild boar (Sus scrofa), and brown tree snake (Boiga irregularis). No formalized invasive species control plans exist within the study area.

FWOP No changes to fish and wildlife resources are anticipated under the future without project conditions.

Waters of the U.S. including Wetlands Existing

Section 404 of the CWA requires that impacts to wetlands should be 1) avoided, 2) minimized, or 3) compensated; in that order of priority. The CWA prohibits the discharge of dredged or fill material into U.S. waters, including wetlands, if any practicable


10

alternative exists. Section 404 of the CWA defines a wetland as meeting all three criteria: soil, vegetation, and hydrology. Wetlands generally include swamps, marshes, bogs, and similar areas. The U.S. Fish and Wildlife Service (USFWS) adopted the USFS hierarchical description of ecoregions for the contiguous United States to regionalize specific inland wetland types based on wetland ecology and likelihood of geological location (Cowardin 1992). The topography of the USEPA defined ‘Piedmont Ecoregion’ and the USFS defined ‘Southern Mixed Forest Province’ allows for the preponderance of streams and wetland development. Streams within these regions are numerous with slower velocity which aids in the creation of marshes and swamps (Bailey 1995). No extensive surveys have been conducted as part of this FRM study to delineate the locations of jurisdictional wetlands within the boundaries of the study area. A review of the USFWS National Wetland Inventory Wetlands Mapper indicates that the presence of various biological wetlands exist within the study area. Figure 7: Sweetwater Creek Watershed Wetland Types shows the potential presence for wetlands within the study area, generally occurs surrounding the tributaries. Predominance of the study area by wetland types include freshwater forested and shrub wetland and freshwater emergent wetland along the riparian zones of the tributaries. Forested and shrub wetland is described as woody wetlands such as forested swamps or shrub bogs. Freshwater emergent wetlands include herbaceous marches, fens, swales, or wet meadows.

FWOP The greatest national threat to riparian zone wetlands results from infrastructure development; however Cobb County’s floodplain management limits the likelihood of development within these areas. As such, potential wetlands throughout the study area would remain functional in the near future without project conditions; however, the study area would experience a less than 1% increase in flooding events over the 1% ACE storm event. Over a long term period, an increase in flooding frequency could have the potential to alter the three components of wetland habitat: soil, hydrology, and vegetation. As stated in Section 2.5.1 Vegetation, an increase in flooding events has the potential to alter chemical composition of soils. In addition, increased flooding frequency would stress existing wetland habitats by disrupting hydrologic intervals necessary to maintain a functional wetland (Erwin 2008). A change to hydric soils combined with the altered hydrology could alter the stable plant ecology suited to wetland habitats. Therefore, under long term FWOP conditions a decrease in wetland habitat could occur within the study area.


11

Figure 7: Sweetwater Creek Watershed Wetland Types

12

Special Status Species Existing

2.5.4.1.1 Endangered Species Act The Endangered Species Act (ESA) “provides for the conservation of species that are endangered or threatened throughout all or a significant portion of their range, and the conservation of the ecosystems on which they depend.” The ESA makes it illegal to “take” a federally-listed species, such as threatened and/or endangered species [T&E], without a permit. “Take” is defined by the ESA as “to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect or attempt to engage in any such conduct.” The USFWS has statutory authority for the assessment of federally-listed or petitioned species. According to the USFWS ESA Overview, “A species is considered endangered if it is in danger of extinction throughout all or a significant portion of its range or threatened if it is likely to become an endangered species within the foreseeable future.” Within Cobb, Paulding and Douglas Counties there are eight federally-listed threatened and endangered species, three of which have a high likelihood to occur in the study area. The most likely listed species are the Northern Long-eared Bat (Myotis septentrionalis) and two plant species, Michaux’s Sumac (Rhus michauxii) and Little Amphianthus (Amphinathus pusillus). All study efforts assessing FRM will consider the possible presence and protection of these species and their habitat. A list of federally-listed species within the study area is included as Table 3. Additionally, the ESA designates critical habitat believed to be essential for federally-listed species conservation. No designated critical habitat for these species exist within the study area.

Table 3: Federally Listed Species – Cobb, Douglas, Paulding Counties Common Name Scientific Name Status

County Cobb Paulding Douglas

Indiana Bat Myotis sodalist E X Northern Long-eared Bat Myotis septentrionalis T X X X Cherokee Darter Etheostoma scotti T X X Etowah Darter Etheostoma etowahae E X Finelined Pocketbook Lampsilis altilis T X Little Amphianthus Amphianthus pusillus T X X Michaux’s Sumac Rhus michauxii E X White Fringeless Orchid Platanthera integrilabia T X

Key 1: T=Threatened; E=Endangered; X=listed

2.5.4.1.2 Migratory Bird Treaty Act The Migratory Bird Treaty Act (MBTA) makes it illegal to “take, possess, import, export, transport, sell, purchase, barter, or offer for sale, purchase, or barter” a species identified in 50 CF 10.13. The USFWS has statutory authority and responsibility for enforcing the MBTA under 16 U.S.C. 703-712. Migratory species protected by the MBTA are internationally protected through conventions between the U.S. and Canada, Mexico, Japan, and Russia. Any species protected through one or more of the four

13

international conventions is qualified for protection under the MBTA. The final rule for the revised list of migratory birds is included in Appendix E. Sweetwater Creek River Basin is situated in the Atlantic Flyway Zone. No stopover sites are known to occur within the study area; however migratory birds, such as the American oystercatcher (Haematopus palliates), black-throated blue warbler (Setophaga caerulescens), grouse (Centrocercus spp), least tern (Sternula antillarum), mottled duck (Anas fulvigula), swallow-tailed kite (Elanoides forficatus), and the tricolored blackbird (Agelaius tricolor), occasionally utilize the study area as a resource.

2.5.4.1.3 Bald and Golden Eagle Protection Act The Bald and Golden Eagle Protection Act (BGEPA) prohibits the “taking” of bald eagles (Haliaeetus leucocephalus) or golden eagles (Aquila chrysaetos) as defined in 16 U.S.C. 668-668c. “Take” is defined by the BGEPA as to “pursue, shoot, shoot at, poison, wound, kill capture, trap, collect, molest or disturb.” “Disturb” is further defined as “to agitate or bother a bald or golden eagle to a degree that causes, or is likely to cause, based on the best scientific information available, 1) injury to an eagle, 2) a decrease in its productivity, by substantially interfering with normal breeding, feeding, or sheltering behavior, or 3) nest abandonment, by substantially interfering with normal breeding, feeding, or sheltering behavior." The BGEPA extends to activities occurring near nests when eagles are not present. According to the National Bald Eagle Management Guidelines dated May 2007, included in Appendix E, bald eagles primarily nest near aquatic habitat in mature or dead trees. Man-made structures such as powerpoles and communication towers also serve as nesting sites for some bald eagles. Bald eagle nests are distinctly large at four to six feet in diameter and three feet deep weighing more than 1,000 pounds. Nests are generally constructed with large sticks and lined with soft and pliable greenery such as moss, grass, or lichens. No surveys have been conducted as part of this FRM study to identify eagles and/or their nests within the study area.

FWOP The USFWS continually assesses federally-protected species under the ESA and MBTA. Species may be listed, down-listed, or de-listed from the T & E species list and/or added or removed from the migratory bird list. Wildlife habitat under future without project conditions would remain the similar to existing conditions.

Wildlife Corridors Existing

Wildlife corridors act as links between fragmented habitats to provide important routes of migration for a variety of wildlife, including terrestrial, aquatic and airborne animals. The Sweetwater Creek River Basin is comprised of forested and riparian zones with few isolated habitats. Areas within the more developed portions of the study area show pockets of degraded habitat.

14

FWOP Wildlife corridors within the study area under the future without project condition would be subject to local municipality land use; however no changes in corridor connectivity would occur as a result of the less than 1% increase in flooding frequency for the 1% ACE storm in FWOP conditions.

2.6 Cultural Resources As per the requirements outlined in Section 106 of the National Historic Preservation Act (NHPA), the lead Federal agency must consider the effects of the proposed action on historic properties. The USACE, Mobile District is also required to assess both direct and indirect effects of the action on historic and cultural resources under the National Environmental Policy Act (NEPA) as defined in 40 CFR 1508.8. In order to take into consideration potential impacts to historic properties (i.e., archaeological sites, buildings, structures, objects, or districts) listed on or eligible for the National Register of Historic Places (NRHP) Mobile District Archaeologists conducted archaeological background research of the study alternatives and recommended plan. Background research sources included Georgia’s Natural, Archaeological, and Historic Resources GIS (GNAHRGIS) and previous cultural resources reports on file at the USACE, Mobile District office.

Existing Cultural Resource Setting

2.6.1.1.1 Prehistoric Period Several archaeological sites and historic properties are present within Cobb, Douglas, and Paulding Counties that are important to local, regional, and national history. There are numerous sites and properties recorded within these three counties including prehistoric and historic archaeological sites. While the prehistoric occupation in Georgia began in the Paleoindian Period, the earliest archaeology sites identified within the Sweetwater Creek watershed study area date to the Early Archaic period showing that this area has been occupied since at least 6000 B.C. The majority of prehistoric archaeological sites are identified as lithic scatters and other limited occupation sites, with the exceptions of archaeological site 9PA64, a possible mound and historic burial site, and 9DO66, a multi-component village site. Sweetwater Town (9DO66) is a multi-component village site, with documented occupations in the Early Archaic to Late Woodland periods. The village was also occupied by the Cherokee during the historic period.

2.6.1.1.2 Historic Period The state of Georgia, particularly the area surrounding the City of Atlanta was one of the main stages for some of the most important battles of the Civil War. The Atlanta Campaign is considered a huge turning point in the Civil War. Due to the study area’s proximity to known major Civil War sites, the area has great potential for Civil War resources. . Of particular interest is the Sweetwater Manufacturing Company, a mill located along Sweetwater Creek within the study area. This mill was raided and burned by Union soldiers during the war in an attempt to hinder the operation of Confederate

15

soldiers. After it’s burning the mill was never rebuilt.. Currently it stands as a partial five story building with remnants of foundations of over a dozen buildings.x. It is one of the main attractions of Sweetwater Creek State Park.

2.6.1.1.3 Historic Structures In the course of the cultural resources background review, it was found that the state of Georgia and two of the counties within the study area commissioned three separate historic resources surveys including: the GA Historic Resources Survey commissioned in 1997, the Historic Resource Survey of unincorporated Cobb County commissioned in 2005, and the “FindIt” Paulding County Survey commissioned in 2006. These surveys produced results that showcase the agricultural nature of the study area with the majority of structures consisting of domestic residential structures showing elements of agriculture including but not limited to field systems, livestock, and chicken coops. The style of structures vary from craftsman, to colonial revival, to Victorian. The oldest structure in the study area was constructed in 1834 and the newest structure on this inventory list was constructed in 1959. Paulding County showcases more diversity with a number of business offices, cemeteries, stores, and historic districts. Paulding County also contains a masonic lodge dating back to 1890. Douglas County had the least amount of structures with 2 structures included in the inventory; a residence built around 1844 and a doctor’s office built around 1879. None of these structures are within the buyout parcels. One of the most predominate existing historic structures in the area is the Sweetwater Manufacturing Mill or New Manchester Mill (9DO10) located in Douglas County. The remnants of the 19th century mill can be seen and visited along Sweetwater Creek at the Sweetwater State Park. The mill is significant in showcasing the past industrial complex in the Atlanta area around the 1850s. In addition to 9DO10 multiple 19th to 20th century structures, sites, and farmsteads have been identified within the study area. Including archaeological site 9PA56, a late 19th to mid-20th century farmstead which has been previously identified as eligible for listing on the NRHP. Being that the study area has rural and undeveloped areas with limited cultural resources survey coverage there is a high potential for the presence of additional un-recorded archaeological sites. There are a number of properties listed on the NRHP within Douglas, Cobb, and Paulding Counties (Table 4). These include: the Clarkdale Historic District, the Israel Causey House, the Butner-McTyre General Store and the New Manchester Mill (9DO10). The Clarkdale Historic District characterizes the industrial complex that was prevalent in the era in the late 19th and early 20th centuries. The historic district consists of a textile factory and mill and the associated village that includes residential and community buildings such as a ball field, tennis court, and swimming pool. Another regionally and nationally important structure listed on the NRHP is the Israel Causey House. This structure is one of the few remaining structures of the plain style in Georgia. It was constructed during the Gold Rush and was inhabited by Cobb County’s pioneer settlers. The house is surrounded by Sweetwater Town (9DO66) and is associated with Cherokee removal in the 1830s. One other NRHP structure within the

16

study area is the Butner-McTyre General Store. This general store is one of the last standing structures of its type from its time period (late 19th century) in the state of Georgia. None of these listed historic properties are located within the recommended plan.

Table 4: NRHP listed properties within the study area. Resource Name/Site Trinomial County NRHP Status Type of Site

Israel Causey House Cobb Listed Dwelling Butner-McTyre General Store Cobb Listed Store

Clarkdale Historic District Cobb Listed Historic District Sweetwater Manufacturing

Company/9DO10 Douglas Listed Mill

Results of Background Research

The primary source for background research conducted for this project was GNAHRGIS as well as cultural resources assessment reports on file at the USACE, Mobile District office. During the background research the Mobile District archaeologists documented numerous previously identified resources in within a mile radius of all proposed work areas within the project alternatives. These previously recorded archaeological sites are summarized in Table 5 and site locations are provided in Figure 8. While several of these archeological sites are located within the work areas associated with the alternatives examined in the study, none are located within the recommended plan. A total of seven previously recorded archaeological sites are located within a mile of the parcels included in the recommended plan. These archaeological sites are summarized in Table 6 and site locations are provided in Figure 9.

Table 5: Previously Recorded Archaeological Sites within in a mile radius of all Alternatives.

Site Number Component(s) Eligibility 9DO66 Mid archaic, early woodland, protohistoric

multicomponent village Eligible

9PA56 Late 19th to mid-20th century rural farmstead Eligible 9CO132 Late archaic lithic scatter Ineligible 9CO141 Archaic lithic scatter Ineligible 9CO740 Prehistoric lithic scatter Ineligible 9CO503 Undetermined prehistoric Ineligible 9DO175 Undetermined prehistoric lithic scatter, 19th-20th

century Ineligible

9DO176 Middle archaic lithic scatter Ineligible 9PA128 Prehistoric lithic scatter Ineligible 9PA129 Mid-20th century Ineligible 9PA130 Prehistoric lithic scatter Ineligible 9PA136 Prehistoric lithic and historic artifact scatter Ineligible 9PA137 Undetermined prehistoric lithic scatter late- 19th early

20th century artifact scatter Ineligible

9PA292 Woodland lithic scatter Ineligible 9PA293 Undetermined prehistoric lithic scatter Ineligible

17

9PA506 Lithic scatter/pottery scatter Ineligible 9PA506 Prehistoric lithic scatter Ineligible 9PA507 Lithic scatter, isolated historic artifact Ineligible 9PA53 Prehistoric lithic scatter Ineligible 9PA57 Undetermined prehistoric Ineligible 9PA61 Early to mid-20th century wood frame house Ineligible 9PA62 Early to mid-20th century brick house Ineligible 9CO716 Middle archaic lithic scatter Ineligible 9CO295 Prehistoric lithic scatter Undetermined 9CO304

Undetermined

9CO305 Lithic scatter Undetermined 9CO409 Campsite, early archaic, late archaic and woodland Undetermined 9CO410 Historic dump, 19th and 20th century Undetermined 9CO423 Early archaic and 20th century lithic scatter Undetermined 9CO430 Archaic lithic scatter Undetermined 9CO449 Late archaic lithic scatter Undetermined 9CO451 Archaic-woodland campsite Undetermined 9CO474 Archaic Mississippian lithic scatter Undetermined 9CO480 Archaic lithic scatter Undetermined 9CO526 Archaic lithic scatter Undetermined 9DO69 Lithic and ceramic scatter, late

woodland/Mississippian Undetermined

9PA28 Prehistoric lithic scatter Undetermined 9PA29 Prehistoric lithic scatter Undetermined 9PA30 Prehistoric lithic scatter Undetermined 9PA51 Prehistoric upland with lithic and ceramics Undetermined 9PA54 Abandoned historic cemetery Undetermined 9PA55 Historic farmstead Undetermined 9PA58 Limited occupation site, woodland/Mississippian Undetermined 9PA59 Undetermined prehistoric Undetermined 9PA63 Early 20th century steel bridge Undetermined 9PA64 Possible mound with potential historic graves Undetermined

18

Figure 8: Location Map of Previously Recorded Archaeological Sites and NRHP

Listed Properties within in a mile radius of all project alternative work sites.

19

Figure 9: Location Map of Previously Recorded Archaeological Sites within in a

mile radius of all proposed buyout locations.

20

Table 6: Previously Recorded Archaeological Sites within in a mile radius of the proposed parcel locations for the Recommended Plan.

Site Number

Component(s) NRHP Eligibility

9DO66 Possible village and mound site Eligible

9CO740 Prehistoric lithic scatter Ineligible

9CO295 Prehistoric lithic scatter Undetermined 9CO409 Campsite, early archaic, late archaic and woodland Undetermined 9CO410 Historic dump, 19th and 20th century Undetermined 9CO449 Late archaic lithic scatter Undetermined 9CO451 Archaic-woodland campsite Undetermined

. FWOP

Previously unidentified cultural resources within the study area under the future without project condition would be subject to continued flooding; which has the potential to impact the NRHP eligibility of resources.

2.7 Sociological Resources Flooding and Flood Damages

Existing 2.7.1.1.1 Existing Flooding

Updated floodplains delineation, to include the floods of late 2009 to present, are part of the existing and future without project condition. Conditions in relation to flood risks are anticipated to slightly deteriorate with less than a 1% increase in peak runoff. Sedimentation from the 2009 flood reduced the channel capacity of Sweetwater Creek and future sediment accretion is possible from another large storm. Furthermore, development in the area with land use changes will continue, affecting the movement of sediment into and down the stream. Local stormwater management regulations will prevent the quantity of overland flow from changing. However, hydrologic timing resulting of the local runoff from developed sites may result in higher peak flow elevations, increasing the height and extent of the floodplain.

2.7.1.1.2 Existing Flood Damages The existing structure inventory within the floodplain contains 2,230 structures on 1,902 parcels. Residential structures account for 1,959 of structures, with the remaining 271 being nonresidential. 62 structures are located within the Buttermilk reach; 69 structures within the Mill Creek reach; 632 structures within the Noses Creek reach; 133 structures within the Olley Creek reach; 220 structures within the Powder Springs Creek reach; and 1,114 structures within the Sweetwater Creek reaches. Table 7 and Table 8 summarize the number of structures in each reach along with their depreciated replacement cost and vehicle depreciated replacement cost in FY 2017 dollars. For more detail on how this was developed see Appendix A.

21

Table 7: Total Depreciated Replacement Value of Study Area

Reach

Structures Total

Structure Value

Total Content Value

Total Vehicle Value

Total Value

Residential Non-Residential Total

Buttermilk Creek 46 16 62 $9,010 $5,588 $475 $15,073

Mill Creek 62 7 69 $6,242 $6,030 $641 $12,913 Noses Creek 589 43 632 67171 $64,093 $6,077 $137,341 Olley Creek 116 17 133 $35,570 $15,798 $1,199 $52,567

Powder Springs Creek 189 31 220 $50,829 $32,430 $1,912 $85,171

Upper Sweetwater

Creek 63 2 65 $6,493 $6,439 $651 $13,583

Middle Sweetwater

Creek 725 86 811 $79,103 $58,847 $5,054 $143,004

Lower Sweetwater

Creek 169 69 238 $181,229 $79,509 $1,220 $261,958

Total 1,959 271 2,230 $435,647 $268,734 $17,229 $721,610

22

Table 8: Existing Condition Mean Expected Annual Damages (x 1,000, 2017 Prices)

Reach Structure Type Expected Damages Buttermilk Creek Residential $6

Nonresidential $1 Total $7

Mill Creek Residential $68 Nonresidential $0 Total $68

Noses Creek Residential $499 Nonresidential $0 Total $499

Olley Creek Residential $41 Nonresidential $11 Total $52

Powder Springs Creek Residential $20 Nonresidential $1 Total $21

Upper Sweetwater Creek Residential $23 Nonresidential $6 Total $29

Middle Sweetwater Creek Residential $327 Nonresidential $96 Total $422

Lower Sweetwater Creek Residential $161 Nonresidential $96 Total $257

Total Residential $1,144 Nonresidential $211 Total $1,355

FWOP

2.7.1.2.1 FWOP Flooding In 2016, USACE issued Engineering and Construction Bulletin No. 2016-25 (hereafter, ECB 2016-25), which stipulated that climate change be considered for all federally funded projects in planning stages. A qualitative analysis of historical climate trends, as well as assessment of future projections was provisioned by ECB 2016-25. Even if climate change does not appear to be an impact for a particular region of interest, the formal analysis outlined in ECB 2016-25 results in better informed planning and engineering decisions. The qualitative climate change assessment showed an increase in flooding frequency at a rate of less than 1% change in flows for the 1% ACE event (Appendix B), however a

23

literature review on climate change in the southeast indicates the potential for more extreme storms in the future. The future 2% ACE Floodplain is shown in Figure 10.

Figure 10: 2% Annual Chance of Exceedance Floodplain Extents

24

2.7.1.2.2 FWOP Flood Damages Changes in the structure inventory as stated in Section 2.3.2 contribute to increased flood damages. Table 9 shows how the average annual damages change between the existing and FWOP.

Table 9: Existing vs. Future Mean Expected Annual Damages (x 1,000, 2017 Prices)

Reach Structure Type Existing Damages

FWOP Damages

Change in Damages

Buttermilk Creek Residential $6 $6 $0 Nonresidential $1 $1 $0 Total $7 $7 $0

Mill Creek Residential $68 $76 $8 Nonresidential $0 $0 $0 Total $68 $76 $8

Noses Creek Residential $499 $515 $16 Nonresidential $0 $0 $0 Total $499 $515 $16

Olley Creek Residential $41 $41 $0 Nonresidential $11 $11 $0 Total $52 $53 $1

Powder Springs Creek Residential $20 $21 $1 Nonresidential $1 $1 $0 Total $21 $22 $1

Upper Sweetwater Creek

Residential $23 $339 $316 Nonresidential $6 $7 $1 Total $29 $32 $3

Middle Sweetwater Creek

Residential $327 $308 -$19 Nonresidential $96 $26 -$70 Total $422 $335 -$87

Lower Sweetwater Creek

Residential $161 $170 $9 Nonresidential $96 $99 $3 Total $257 $270 $13

Total Residential $1,144 $1,194 $50 Nonresidential $211 $220 $9 Total $1,355 $1,413 $58

Hazardous Toxic Radiological Waste

Existing An Environmental Site Assessment (ESA) was conducted for the Sweetwater Creek FRM Feasibility Study for the presence of Hazardous, Toxic, and/or Radiological Waste (HTRW) sites within the study area. The intent of the ESA was to evaluate areas for the

25

presence of environmental contamination as described in Standard Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process. Available environmental records and databases were reviewed to identify known areas of hazardous material/waste storage or disposal within the entire watershed area. An environmental database search identified 177 properties, with complete address information, within 1000 feet of the stream centerlines for each area. Sites with incomplete addresses, coordinates or other database information were not plotted. A site inspection was completed to visually inspect each of the alternative study areas for evidence of recognized environmental conditions (RECs). Properties were photographed to document conditions at the time of the inspection and interviews were completed to document conditions in the area known by local residences, officials, and workers. Observations of RECs are available in the USACE “Phase I Environmental Site Assessment for Sweetwater Creek Feasibility Study, Douglas, Paulding, and Cobb Counties, Georgia” report. An abbreviated version of this report can be found in Appendix E. The full version will be made available upon request.

FWOP No additional HTRW sites are anticipated to be introduced as a result of continued localized flooding.

Noise Existing

Ambient noise of the study area is consistent with rural and suburban zones. The study area is located 12 miles west of the City of Atlanta where heavy traffic, construction, and community events contribute to higher levels of steady noise. Increased noise levels occur within the more developed portions of the study area, i.e. near the City of Austell.

FWOP As local populations increase, noise levels would increase incrementally. Rural sections within the study area would not experience the level of ambient noise that the more urbanized portions of the study area undergo.

Aesthetic Existing

Environmental aesthetics is a philosophical approach to assign appreciation of natural environments. The general aesthetics of the study area comprise of intermittent forested and riparian habitat interspersed with residential, commercial, and communal structures.

FWOP Local aesthetics of the study area for future without project conditions would remain the same.

26

Navigation Existing

There is no commercial navigation within the study area. The nearest navigable waterway is considered the Chattahoochee River below Walter F. George Lock and Dam. The USACE, does not maintain a navigation channel in the Chattahoochee River below Lake Sidney Lanier.

FWOP Future without project conditions would resemble existing conditions. No dredging activities within the Chattahoochee River would occur in the near future.

Socioeconomics Existing

Based on the 2016 American Survey by the U.S. Census, a breakdown of the socioeconomics within the study area is included in Table 10: Study Area Demographics, Table 11: Study Area Housing, Table 12: Study Area Income, Table 13: Study Area Occupation, and Table 14: Study Area Industry.

Table 10: Study Area Demographics Subject Cobb

County Douglas County

Paulding County Georgia United States

Total population 748,150 142,224 155,825 10,310,371 323,127,515

Male 48.30% 48.40% 48.60% 48.70% 49.20% Female 51.70% 51.60% 51.40% 51.30% 50.80% Median age (years) 36.5 36 36.4 36.5 37.90 White 58.70% 47.30% 74.30% 58.70% 72.60% Black or African American 27.00% 47.40% 22.10% 31.60% 12.70% American Indian and Alaska Native 0.40% N N 0.40% 0.80%

Asian 5.30% 1.60% N 3.90% 5.40% Native Hawaiian and Other Pacific Islander N N N 0.10% 0.20%

Hispanic or Latino (of any race) 12.90% 9.40% 6.10% 9.30% 17.80% Some other race 4.90% N N 2.90% 5.10% Two or more races 3.50% 1.70% N 2.50% 3.20%

Table 11: Study Area Housing Subject Cobb

County Douglass County


Total housing units 297,399 52,194 54,840 4,219,103 135,702,775 Total households 277,949 48,901 53,249 3,686,135 118,860,065 Average household size 2.66 2.88 2.91 2.73 2.65

27

Table 12: Study Area Income Subject Cobb


Paulding County Georgia United

States Median household income (dollars) 70,947 62,445 60,856 53,559 $57,617 Median family income (dollars) 87,542 75,046 68,825 65,018 $71,062 Per capita income (dollars) 35,722 28,004 25,730 28,183 $31,128 Population below the poverty line 9.60% 12.50% 8.70% 16.00% 14.00%

Table 13: Study Area Occupation Subject Cobb



Civilian employed population 16 years and over 392,106 70,398 74,892 8,085,411 152,571,041

Management, business, science, and arts occupations 45.00% 35.40% 33.10% 36.40% 37.60%

Sales and office occupations 23.90% 24.40% 26.70% 24.10% 23.30% Service occupations 15.90% 16.10% 18.20% 16.70% 18.10% Production, transportation, and material moving occupations 8.20% 14.80% 11.30% 13.30% 12.20%

Natural resources, construction, and maintenance occupations 7.10% 9.30% 10.70% 9.40% 8.80%

Unemployment Rate 4.50% 7.50% 3.00% 6.00% 5.80%

Table 14: Study Area Industry Subject Cobb


Paulding County Georgia United

States Educational services, and health care and social assistance 17.60% 19.00% 17.10% 20.20% 23.00%

Retail trade 11.60% 12.10% 13.90% 11.90% 11.50% Professional, scientific, and management, and administrative and waste management services

16.70% 9.60% 11.40% 12.10% 11.40%

Manufacturing 6.80% 8.50% 9.40% 10.60% 10.10% Arts, entertainment, and recreation, and accommodation and food services 10.60% 9.80% 8.50% 9.80% 9.80%

Finance and insurance, and real estate and rental and leasing 9.40% 5.50% 8.00% 6.20% 6.60%

Construction 6.80% 8.00% 11.40% 6.70% 6.40% Transportation and warehousing, and utilities 5.40% 9.90% 6.20% 6.20% 5.20%

Other services, except public administration 5.30% 5.70% 5.80% 4.90% 4.90%

Public administration 3.20% 5.20% 4.70% 5.00% 4.60% Wholesale trade 3.30% 4.10% 2.30% 3.00% 2.70% Information 3.10% 2.60% 1.20% 2.30% 2.10% Agriculture, forestry, fishing and hunting, and mining 0.20% 0.00% 0.10% 1.10% 1.70%

28

FWOP There was no anticipated change to the socioeconomics between the existing and FWOP condition.

Public Safety Existing

Public safety with regards to flood risk within the study area experiences increased demand during localized flooding events. Emergency vehicles can expect delays reaching 30 minutes due to the need to avoid impacted roads during flooding events.

FWOP Public safety with regards to flood risk under future without project conditions would continue to decline as the frequency of localized flooding increases.

Recreation Existing

Local recreational parks throughout the study area include sports fields and municipal playgrounds. At the southern end of the study area lies Sweetwater Creek State park which encompasses 2,549 acres of land and 215 acres of the George Sparks Reservoir lake surface. According to the Georgia Department of Natural Resources State Parks and Historic Sites, Sweetwater Creek State Park is the most visited recreational park in the State of Georgia and received approximately 770,000 visitors in 2017 (personal communication, February 2, 2018). The State Park is open yearlong and accommodations within the State Park include yurts, tent campsites, picnic shelters, playgrounds, fishing docks, boat ramp, a seasonal bait shop, an event room and visitor center. A sample of outdoor activities include birding, fishing, hiking, picnicking, geocaching, family reunions, kayaking, canoeing, paddle-boarding, and weddings.

FWOP Future without project conditions would result in more frequent flooding. Flooding events would result in temporary closures of affected areas which in turn would result in lost revenue. 3.0 Plan Formulation

Problems, opportunities, and constraints were identified based on the existing conditions and the FWOP. Objectives were developed from the identified problems and opportunities in the study area.

Problems The existing problems in the study area include:

• Routine rainfall events cause flooding along Sweetwater Creek increasing flood risk and damaging residential and commercial structures throughout Cobb County

o The Cities of Austell and Powder Springs and the surrounding areas experience the most extensive and frequent flooding in the study area

• Emergency services disrupted during routine flood events

29

• Reduced channel conveyance from continual sedimentation from erosion and run-off

Opportunities

The existing opportunities in the study area include:

• Reduce flood damages along Sweetwater Creek and its tributaries within Cobb County

• Reduce impacts to emergency services during flood events • Reduce stream bank erosion • Improve flood risk communication among stakeholders • Address environmental degradation of the channel and its habitat for the

creatures therein

Objectives The planning objectives for the 50-year period of analysis from 2023 to 2073, within the Sweetwater Creek watershed inside Cobb County, are:

1. Reduce average annual flood damages 2. Reduce number of structures impacted 3. Reduce response times for emergency services during flood events 4. Increase access to emergency services during flood events

Constraints

Impacts to the below planning constraints should be avoided when able, minimized where possible, and mitigated if there are any resulting impacts.

1. Induced flooding in developed areas 2. Impacts to cultural resources 3. HTRW sites 4. Impacts to T & E species

3.2 Management Measures

A number of non-structural and structural measures were considered for alternative plan development. The measures considered were based on local input, local conditions, and professional judgment. The measures considered for Sweetwater Creek consisted are shown in Table 15.

30

Table 15: Measures Considered Measure Various Methods to Develop Measure

Non

-Str

uctu

ral

Mea

sure

s

Structure Relocation/Evacuation (Buyouts)

Elevating Structures

Flood Proofing Structures

Flood Warning System

Flood Plain Regulation

Stru

ctur

al M

easu

res Modifying Channel Capacity Clearing and snagging, Channel deepening and/or

widening, Modifying bridge crossings and culverts

Retention/Attenuation In-channel/Off-channel, Rehabilitation/Modification of existing dams

Levees/Floodwalls

Diversion High flow, Full flow, Channelized tunnel

Screening of General Measures

The criteria for screening the initial measures by using professional judgment included: 1) was it implementable, 2) not likely to induce flooding, 3) meet the project objectives and 4) relative effectiveness to other measures. Many measures were eliminated because they were not able to be implemented. Elevating structures and flood proofing were removed because the type of construction (i.e. slab on grade foundations) in the flood prone areas does not allow for elevating the structures. Flood plain regulation, or regulating the development in floodplains, has already been implemented by the NFS and so was not carried forward. Other measures would not meet the project objectives so they were not carried forward. Clearing and snagging would only meet project objectives for a single event, after which it would be required again. Therefore, it was eliminated because it did not meet the project objectives. A flood warning system would not meet project objectives, but could be coordinated to support the success of any alternative carried forward. Finally levees and floodwalls were not considered effective when compared to other alternatives. Floodwalls and levees alignments would only be able to reduce the flood risk for one to three structures from a single structure.

31

3.3 Site Specific Measures and Screening After screening the initial measures, the USACE, Mobile District developed multiple alternative plans from the remaining measures. These plans included: channel modifications, diversions, retention areas, relocation/evacuation (buyout), and flood warning systems.

Channel Modification The channelization of Sweetwater Creek would begin upstream of the City of Austell and in order to not induce flooding would need to extend downstream to the rapids in Sweetwater Creek State Park. The objective of the measure is to increase channel conveyance through the creation of a more optimal channel design that will reduce flood elevations and concurrently provide a more stable channel. Clearing and snagging would only provide flood risk relief for a single event so it was eliminated since it would not achieve the project objectives without constant maintenance. Modifying bridges and culverts was removed since the ponding that occurs on the upstream side of the structures does not appear to be causing damages to adjacent property owners. Sweetwater Creek has a small elevation change from the Cobb/Paulding County line to Sweetwater Creek State Park. In the 44,000 feet of creek the elevation drops by only 20 feet. Because of the small elevation change, the channel deepening and/or widening would need to extend to the rapids and falls in Sweetwater Creek State Park in order to not induce flooding. The location of the channel modification is shown in Figure 11.

Diversion Diversion channel alternatives were investigated. Alignments included connecting tributaries, such as Noses and Ollie Creek, as well as bypassing developed areas on Sweetwater Creek itself. One alignment would require a tunnel under the City of Austell that would be 3 12x12 foot culverts in order to pass sufficient flow. The diversion alignments are shown in Figure 11.

32

Figure 11: Channel Modification and Diversion Measures

Full flow diversion was eliminated since it could negatively affect T&E species potentially occurring within the area, while a high flow diversion could achieve the same benefits without the T&E species risk. The high hydrologic and hydraulic connectivity in the basin before Powder Springs Creek joins Sweetwater Creek make diversions in this portion of the basin have negligible impacts on the floodplain. After further investigation into the topography and geotechnical data, diversions were fully eliminated because it would require pumps or extensive excavation in order to develop the needed grade for water to flow from upstream to downstream.

Retention Areas No off-line retention sites were identified that would provide a measurable hydrologic or hydraulic change in the flood effected areas. In-line sites of various sizes and locations on Sweetwater Creek and its tributaries were identified. The locations of the retention measures are shown in Figure 12.

33

Figure 12: Possible Retention Sites

Some of the sites were small and not close enough to flood damages to affect any measurable change even when combined with other measures and retention sites. Other retention sites, when the retention structure was made large enough to affect a change, could not be tied into high ground. Those sites were removed from further consideration.

Retention Site Combinations Combinations of retention sites were developed as part of capturing additional benefits through modified designs of the same structure. One retention combination was to combine all the sites to determine a relative maximum effect from retention.

Structure Relocation/Evacuation (buyout) Relocation/Evacuation is purchasing residential and commercial structures affected by flooding at various probable ACEs. After the structures are purchased they would be demolished and the site would be left undeveloped. Owners who are affected by the buyouts would be offered relocation benefits as part of this measure. The floodplains used for the possible by outs ranged from the 10% to the 1% ACE.

Flood Warning System A reverse 911 style flood warning system, that could send a text to a cell phone, would help alert those in the area to the potential for a flood event. Sweetwater Creek, Powder Springs Creek, Noses Creek, and Olley Creek all have USGS stream gauges that could be used to trigger the notifications for an area while allowing time for those in

34

the area to avoid the flood waters. However, this has been implemented by Cobb County so was not carried forward.

3.4 Final Array of Alternatives The alternatives carried forward for the final array are detailed in the following sections.

Alternative 1: Relocation/Evacuation of Structures (Buy Outs) The evaluation of Alternative 1 included four levels of relocation/buyouts based on the annual percent chance of exceedance floodplain in order to identify the most justifiable level of buyouts. Alternative 1 through 1.3 were purchasing structures with first floor elevations lower than the floodplains for the 10, 4, 2, or 1 percent ACE storms. Table 16 shows the number of structures that would be purchased as part of each alternative based on the ACE floodplain buyout.

Table 16: Structures for Purchase by Annual Chance of Exceedance Alternative Percent ACE Number of Structures

1 10 20 1.1 4 26 1.2 2 66 1.3 1 117

Alternative 2: Brown Road Detention Alternative

Alternative 2 consists of an in-line dry detention facility on Sweetwater Creek, located just upstream of Brown Road in Cobb County, creating up to 9,000 acre-feet of flood storage. The objective of the alternative is to temporarily detain floodwaters from the approximately 100 square miles that drain to the facility location. By temporarily detaining floodwaters, the facility will reduce the peak downstream discharges. This alternative would reduce flood risk along a section of Sweetwater Creek and along the Tributaries of Mill Creek, Power Springs Creek, Noses Creek, Olley Creek and other small tributaries which experience backwater flooding from Sweetwater Creek. The facility would consist of a 1,400 feet long, 33 feet high structure built approximately perpendicular to Sweetwater Creek and its adjoining floodplain. The outlet works of the structure would consist of a multi-stage concrete slot with vertical side walls discharging into a stilling basin downstream of the structure.

Alternative 4: Austell Channel Modification Alternative 4 consists of a channel modification from near the C.H. James Parkway to the rapids in Sweetwater Creek State Park near the historic mill site (14.2 miles). The channel would be widened to 80 feet and would have 2V:1H side slopes. The length of the channel modification is approximately 74,000 linear feet and would remove approximately 3 million cubic yards of material from the channel. The objective of Alternative 4 is to increase channel conveyance through the creation of a more optimal channel design that will reduce flood elevations and concurrently provide a more stable channel. Dredged material would be placed at city approved disposal areas within 4 miles of the project.

35

Alternative 5H: Multiple Detention Structures on Sweetwater Creek Alternative 5H consists of two in-line dry detention structures on Sweetwater Creek. The detention sites would be dry within 24 hours after an event. The first is a 10 feet high structure upstream of Bakers Bridge Road in Paulding County near the Douglas and Paulding County line. This approximately 400 acre detention site would hold water in both Paulding and Douglas Counties. The second is a 33 feet high structure upstream of Brown Road in Cobb County near the Paulding County line. This approximately 900 acre detention site would hold water in both Paulding and Douglas Counties. These structures would provide a combined 18,900 acre-feet of flood storage in the basin. The objective of the alternative is to temporarily detain floodwaters along Sweetwater Creek. By temporarily detaining floodwaters, the facility will reduce the peak downstream discharges. The outlet works on each structure would consist of a multi-stage concrete slot with vertical side walls discharging into a stilling basin downstream of the structure. The outlet works for the site upstream of Brown Road would allow a reduced flow when compared to the structure in Alternative 2 to further reduce downstream water surface elevations.

Alternative 5D: Multi-Subbasin Detention Alternative 5D consists multiple inline dry detention structures with three on Sweetwater Creek, one on Powder Springs Creek, one on Ollie Creek, and one on Mill Creek. All the detention sites would be dry within 24 hours after an event. The first on Sweetwater Creek is a 24 feet high structure upstream of Bakers Bridge Road in Paulding County near the Douglas and Paulding County line. This approximately 400 acre detention site would hold water in both Paulding and Douglas Counties. The second on Sweetwater Creek is a 15 feet high structure upstream of Highway 92 in Paulding County. This approximately 250 acre detention site would hold water in Paulding and Douglas Counties. The third on Sweetwater Creek is a 33 feet high structure upstream of Brown Road in Cobb County near the Paulding County line. This approximately 900 acre detention site would hold water in both Paulding and Douglas Counties. The one on Powder Springs Creek is a 25 feet high structure upstream of C.H. James Parkway in Cobb County near the Cobb and Paulding County Line. This approximately 400 acre detention site would hold water in Cobb County. The structure on Ollie Springs Creek is a 29 feet high structure upstream of Flint Hill Rd Southwest in Cobb County. This approximately 250 acre detention site would hold water in Cobb County. The structure on Mill Creek is a 20 feet high structure upstream of Morningside Drive in Paulding County. This approximately 300 acre detention site would hold water in Paulding County. These structures would provide a combined 25,040 acre-feet of flood storage. The objective of the alternative is to temporarily detain floodwaters along Sweetwater Creek. By temporarily detaining floodwaters, the facility will reduce the peak downstream discharges. The outlet works on each structure would consist of a multi-stage concrete slot with vertical side walls discharging into a stilling basin downstream of the structure.

36

Alternative 5J: South Paulding High Detention Short This alternative is an in-line dry detention facility on Sweetwater Creek, located approximately 1 mile upstream of Bakers Bridge Road in Paulding County, creating up to 7,660 acre-feet of flood storage. The objective of the alternative is to temporarily detain floodwaters from the approximately 42 square miles that drain to the facility location. By temporarily detaining floodwaters, the facility will reduce the peak downstream discharges in addition to delaying the timing of the hydrograph peak. The delaying of the hydrograph at the site will have the additional benefit of allowing Mill Creek, which confluences with Sweetwater Creek approximately 7.5 miles downstream of the site, to drain longer before the peak discharge of Sweetwater Creek reaches the confluence, resulting in less coincidental peaks and reducing the combined peak downstream of the confluence for most flood events. This Alternative would reduce flood risk along a section of Sweetwater Creek and along the tributaries of Mill Creek, Powder Springs Creek, Noses Creek, Olley Creek and other small tributaries which experience backwater flooding as a result of Sweetwater Creek flooding. The structure would consist of a 1,500 feet long, 19 feet high structure built approximately perpendicular to Sweetwater Creek and its adjoining floodplain. The outlet works of the structure would consist of a multi-stage concrete slot with vertical side walls discharging into a stilling basin downstream of the structure.

Final Alternative Array Summary Table 17 shows a brief summary of each of the measure in an alternative and Table 18 shows the Measures that make up each alternative. The location of the measures is shown in Figure 13.

37

Table 17: Measures in Final Array Summary Measure Description

10% ACE Buyouts (20 Structures)

Buyout of structures with 1st floor elevation lower than 10% ACE storm







SC1 A 24 feet high structure upstream of Bakers Bridge Road in Paulding County near the Douglas and Paulding County line

SC1s A 19 feet high structure upstream of Bakers Bridge Road in Paulding County near the Douglas and Paulding County line

SC2 A 15 feet high structure upstream of Highway 92 in Paulding County

SC6 A 33 feet high structure upstream of Highway 92 upstream of Brown Road in Cobb County

SC6LF A 33 feet high structure upstream of Highway 92 upstream of Brown Road in Cobb County with a smaller outfall structure

MC2 A 20 feet high structure upstream of Morningside Drive in Paulding County

PC2 A 25 feet high structure upstream of C.H. James Parkway in Cobb County near the Cobb and Paulding County Line

OC2 A 29 feet high structure upstream of Flint Hill Rd Southwest in Cobb County

Channel Modification A channel modification from near the C.H. James Parkway to the rapids in Sweetwater Creek State Park near the historic mill site (14.2 miles)

Table 18: Measures in Alternatives

Alternative SC1s SC1 SC2 SC6LF SC6 MC2 PC1 OC1 Channelization Buyouts Future Without

Project (No Action)

Alternative 1

Alternative 2

Alternative 4

Alternative 5D

Alternative 5H

Alternative 5J

38

Figure 13: Measures in Final Array

3.5 Comparison of Final Alternatives

Alternatives were screened based on how well an alternative plan 1) accounts for all the required work in order to ensure project objectives (Completeness); 2) achieves the planning objectives (Effectiveness); 3) complies with laws, regulation, and public policy (Acceptability); and 4) achieves the planning objectives in relation to costs (Efficiency).

39

Completeness All alternatives included the required work needed to ensure that the project objectives were achieved. This includes assessing if any additional structures should be bought out if all avenues of egress were cut off by the flood event water surface level used for an alternative. For all alternatives, this included determining likelihood of cultural and natural resources that would need to be protected as part of a projects implementation.

Effectiveness Reduce Average Annual Flood Damages

Average Annual Benefits were used to determine how well an alternative met the objective of reducing flood damages. The benefits were developed using the USACE certified Hydrologic Engineering Center (HEC) River Analysis System (HEC-RAS) and HEC-Flood Damage Reduction Analysis (FDA) models, for hydraulics and economics respectively. The results of the evaluation are shown in Table 19. Table 19: Alternatives Equivalent Annual Damages Reduced(x1000, 2017 Prices)

Reach Damage Category FWOP Alt 1 Alt

1.1 Alt 1.2

Alt. 1.3 Alt 2 Alt 4 Alt

5D Alt 5H

Alt 5J

Buttermilk Creek

Residential $0 $0 $3 $3 $3 $1 $3 $1 $2 $1 Nonresidential $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 Total $0 $0 $3 $3 $3 $1 $3 $1 $2 $1

Mill Creek Residential $0 $0 $0 $0 $0 -$3 $0 -$4 $0 $0 Nonresidential $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 Total $0 $0 $0 $0 $0 -$3 $0 -$4 $0 $0

Noses Creek


Olley Creek Residential $0 $7 $11 $23 $29 $1 $1 $1 $2 $2 Nonresidential $0 $4 $4 $4 $4 $0 -$2 $0 $0 $0 Total $0 $12 $15 $28 $33 $1 $1 $1 $2 $2

Powder Springs Creek


Upper Sweetwater

Creek

Residential $0 $0 $0 $0 $0 -$2 $0 $3 $8 $10 Nonresidential $0 $0 $0 $0 $0 $0 $0 $2 $3 $3 Total $0 $0 $0 $0 $0 -$2 $0 $5 $11 $13

Middle Sweetwater

Creek


Lower Sweetwater

Creek


Total for Stream


40

All levels of buyouts produced more flood damage reduction benefits than the structural alternatives. Channel modification produced the largest benefits from a structural solution. For more information on the benefits and how they were calculated see Appendix A: Economics.

Reduce Number of Structures Impacted Due to uncertainty in the analysis of structures impacted, especially with the structural alternatives, this objective was evaluated based on a qualitative assessment of if an alternative was likely to remove structures from the 1% ACE flood event. The results of that qualitative analysis are shown in Table 20.

Table 20: Reduce Number of Structures Impacted Alternative Likely to Remove

Structures Future Without Project Yes

1 Yes 1.1 Yes 1.2 Yes 1.3 Yes 2 Yes 4 Yes

5H Yes 5D Yes 5J Yes

Reduce Response Times for Emergency Services during Flood

Events The qualitative assessment of whether an alternative would reduce response time was used to assess this objective. For the buyout alternative, it was determined that having less people working and living in floodplains would reduce the calls for emergency services in hard to reach places and thus reduce the response times for the study are as a whole. Structural alternatives were assessed like the buyout alternatives, but also looked to see if the avenues of egress to an area increased. A summary of these results is found in Table 21.

Table 21: Reduced Response Times Qualitative Summary Alternative Would the Change Reduce Response

Times Future Without Project No



41

Increase Access to Emergency Services during Flood Events The qualitative assessment of whether an alternative would increase access to emergency services was used to assess this objective. For the buyout alternative, it was determined that having less people working and living in floodplains would increase access since they would relocate to areas that do not experience as frequent of flooding. Structural alternatives were assessed like the buyout alternatives, but also looked to see if the avenues of egress to an area increased. A summary of these results is found in Table 22.

Table 22: Reduced Response Times Qualitative Summary Alternative Would the Change Increase

Emergency Services Access Future Without Project No



Acceptability

All of the alternatives in the final array complied with laws, regulations, and public policy. This effort includes a qualitative assessment of climate change for the area, as well as a qualitative assessment on how climate change will affect the resiliency of the recommended action. The qualitative climate change analysis shows no impact on the evaluated alternatives nor a change in resiliency from one alternative to the other.

Efficiency Average Annual Net Benefits, which is the average annual benefits minus the average annual costs, was used to determine the efficiency of the alternatives.

Table 23: Alternative Project Costs

Alternative Project First Cost Construction

Period (months)

Interest During Construction Total Cost

Annual O&M Cost

Total Average Annual Cost

1 $4,669,100 36 $189,764 $4,858,864 $0 $179,978 1.1 $5,674,100 48 $312,534 $5,986,634 $0 $221,751 1.2 $15,708,300 60 $1,096,202 $16,804,502 $0 $622,455 1.3 $23,028,400 72 $1,951,896 $24,980,296 $0 $925,294 2 $22,653,000 12 $284,124 $22,937,124 $20,000 $869,612 4 $134,178,600 30 $4,497,869 $138,676,469 $0 $5,136,705

5H $33,141,000 17 $606,903 $33,747,903 $26,000 $1,267,053 5D $152,267,600 29 $4,924,478 $157,192,078 $36,000 $5,858,539 5J $8,631,000 9 $78,552 $8,709,552 $18,000 $340,610

42

Table 24: Cost and Benefit Comparison

Alternative Description Average

Annualized Benefits

Average Annualized

Costs First Cost Net Benefits

1 10 Year Buyouts (20 Structures) $529,820 $179,978 $4,669,100 $349,842

1.1 25 Year Buyouts (26 Structures) $556,540 $221,751 $5,674,100 $334,789

1.2 50 Year Buyouts (66 Structures) $612,190 $622,455 $15,708,300 -$10,265

1.3 100 Year Buyouts (117 Structures) $651,480 $925,294 $23,028,400 -$273,814

2 SC6 $22,270 $869,612 $22,653,000 -$847,342 4 Channelization $142,110 $5,136,705 $134,178,600 -$4,994,595

5H SC1, SC6LF $135,360 $1,267,053 $33,141,000 -$1,131,693 5D All Detention $95,080 $5,858,539 $152,267,600 -$5,763,459 5J SC1S $97,000 $340,610 $8,631,000 -$243,610 Alternative 1 reasonably maximizes net benefits and is therefore the National Economic Development (NED) plan.

Benefit Uncertainty Analysis There is uncertainty in the benefits calculated to identify the NED plan. The uncertainty is shown in Table 25 and also in Figure 14.

Table 25: Benefit Uncertainty Analysis

Probability Net Benefits

Exceeds Indicated Values (2017price levels $1000) given the Annual Cost

Alternative Equivalent Annual Damages Reduced (2017 prices $1000)

0.75 0.50 0.25 Annual Costs

(2017 price levels $1000)

Mean Net Benefits (2017

price levels $1,000)

1 528 306 348 387 180 348 1.1 555 277 330 382 222 333 1.2 610 (101) (24) 63 622 (12) 1.3 649 (390) (298) (182) 925 (276) 2 22 (866) (854) (831) 870 (848) 4 141 (5,033) (5,015) (4,970) 5,137 (4,996)

5H 135 (1,186) (1,156) (1,095) 1,267 (1,132) 5D 158 (5,764) (5,730) (5,655) 5,859 (5,701) 5J 97 (279) (257) (218) 341 (244)

43

Figure 14: 1st and 3rd Quartile Uncertainty for Economically Justified Alternatives

The uncertainty does show that all the structural alternatives have less than a 25% probability of being justified and should not be selected. The uncertainty of the 10% ACE buyouts is the least of the economically justified alternatives and it has the highest possible net benefits at the 25% likelihood of exceedance scenario. This further supports the selection of Alternative 1.0 as the NED and TSP.

3.6 Plan Selection Alternative 1.0 is the NED plan that reasonably maximizes net benefits. Further, of the two justified alternatives, it has the least uncertainty in benefits with the highest possible net benefits of all the plans. There is no critical infrastructure or life safety concerns addressed by Alternative 1.1 that is not also addressed by Alternative 1.0. Therefore Alternative 1.0, the 10% annual chance exceedance buyout, is the TSP. 4.0 Tentatively Selected Plan

Alternative 1.0 is the NED Plan and the TSP. This feature consists of buying out structures whose first floor elevations are lower than the anticipated water surface elevation of the 10% ACE floodplain; this totals 20 structures throughout Cobb County, the City of Austell, and the City of Powder Springs.

4.1 Sites required and Area of Effect The 20 structures in the 1% ACE buyout plan are on 20 different parcels. The parcels are found throughout the Sweetwater Creek Basin. A breakdown of the number of structures to be purchased as part of the relocation/evacuation of the 10% ACE floodplain are shown in Table 26. Of the structures identified in Table 26, a list of all parcels selected for relocation/evacuation in the study area and the associated naming convention, or Parcel ID, is included in Table 27.

0 50000 100000 150000 200000 250000 300000 350000 400000 450000

1

1.1

Average Anual Net Benefits

Alte

rnat

ive

Alternatives 1 and 1.1 Net Benefit Range at 75%, Mean and 25%

44

Table 26: Number of Structure in Tentatively Selected Plan by Reach Reach Number of Structures

Buttermilk Creek 0

Mill Creek 0 Noses Creek 7 Olley Creek 0

Powder Springs Creek 7 Upper Sweetwater Creek 3 Middle Sweetwater Creek 3 Lower Sweetwater Creek 0

Table 27: Tentatively Selected Plan Parcel IDs

Reach Parcel ID Structure Type Upper Sweetwater Creek PID_SCa Residence PID_SCb Residence PID_SCc Residence Middle Sweetwater Creek PID_SCd Service Station PID_SCe Residence PID_SCf Business Powder Springs Creek PID_PCa Residence PID_PCb Residence PID_PCc Residence PID_PCd Residence PID_PCe Residence PID_PCf Residence PID_PCg Residence Noses Creek PID_NCa Residence PID_NCb Auto Repair PID_NCc Residence PID_NCd Residence PID_NCe Residence PID_NCf Residence PID_NCg Residence

4.2 Cost

The costs developed for the TSP included the cost to acquire all the structures and the parcels they sit on, relocation expenses for the residence or business proprietor, and demolition costs for each of the structures. The first costs for implementation of the TSP are $4,669,100. 5.0 Environmental Impacts of the Tentatively Selected Plan

As shown in Figure 15: the buyout of structures within the 10% ACE floodplain comprises a small portion of the entire study area. As such, the potential for adverse environmental impacts are minimal. Table 28: Environmental Impacts Summary lists

45

the effects of the TSP on all environmental resources evaluated within Section 2.0 Existing and Future Without-Project Conditions (No Action Alternative).

Figure 15: Tentatively Selected Plan

46

Table 28: Environmental Impacts Summary Resource Impact

Section Sub-section No Action Recommended Action Topography, Geology

and Soils NE NE

Air Quality NE NE Land Use NE NE

Water Resources NE NE

Sweetwater Creek and Tributaries NE NE

Surface Water Quality NE NE Groundwater NE NE

Biological Resources NE NE Vegetation NE PB Fish and Wildlife NE PB Wetlands NE NE Special Species NE NE Wildlife Corridors NE PB

Cultural Resources Pending Pending Sociological Resources NE NE

Flooding and Flood Damages NE NE

HTRW NE NE Noise NE NE Aesthetic NE PB Navigation NE NE Socioeconomics AE PB Public Safety AE PB Recreation AE AE

Key 1: NE = No Effect; AE = Adverse Effect; PB = Positive Benefit

5.1 Topography, Geology, and Soils Common construction practices for structural buildings involve the use of red clay to set structural foundations. Because the TSP involves the demolition of existing structures it is assumed that no unique topography, geology, or soils exist within the footprint of each location. Each structure would be demolished and the footprint of each site would be re-graded to match surrounding terrain. Therefore, no adverse effects to topography, geology, or soils are anticipated as a result of this TSP.

5.2 Air Quality and Greenhouse Gases The potential for existing structures to contain hazardous materials is moderate. The oldest existing structure dates to 1942. All existing structures would be inspected for the presence of asbestos, toxic mold, and other environmental hazards that could impact air quality as a result of demolition. Should any existing structures contain toxic materials, licensed contractors from the State of Georgia would remove the materials consistent with USEPA and Occupational Safety and Health Administration (OSHA) guidelines.

47

Demolition activities would contribute to a localized temporary increase in dust particles. All demolition activities would be in accordance with Georgia’s Best Management Practices (BMPs) to minimize and contain small particles. Equipment used for demolition would be in accordance with state standards. Equipment emissions during demolition would be minor and localized. Upon completion of all demolition activities any localized minor increases in dust or emissions would revert to pre-demolition levels. Therefore, the TSP would have no effect on air quality.

5.3 Land Use The TSP would result in the conversion of 20 structures located within the 10% ACE floodplain in Cobb County, Georgia shown in Figure 15: from residential use to vacant use. As shown in Figure 4: Sweetwater Creek Watershed National Land Cover Database Overview, the locations of these structures lie within low to medium intensity developed areas. The demolition of each parcel would neither individually or cumulatively adversely affect the surrounding land use of the study area.

5.4 Water Resources Sweetwater Creek and Tributaries

No construction or demolition activities would be implemented within Sweetwater Creek or its tributaries; therefore no impacts to the resources are anticipated.

Surface Water quality Table 29 lists parcels adjacent to the USEPA 303(d) listed streams identified in Section 2.4.2 Surface Water quality. Prior to demolition a National Pollutant Discharge Elimination System (NPDES) stormwater permit would be obtained. All demolition activities would incorporate BMPs to minimize and contain runoff. Though no surveys have been completed to identify State waters within the Study Area, sites identified for the TSP and referenced in Table 30: Tentatively Selected Plan Identified Properties and Likelihood of Nearby State Waters, demolition activities within parcels PC2, PC3, PC4, and PC5 have the highest likelihood of encroaching within a GEPD stream buffer zone. Aerial examination of all other sites show structure locations well beyond the maximum GEPD stream buffer zone; however all parcels will be surveyed for the presence and/or classification of State waters prior to implementation. Should the surveys show the potential for the TSP to encroach on the GEPD stream buffer zone, a stream buffer variance will be obtained prior to implementation. Therefore, no impacts to surface-water quality are anticipated.

48

Table 29: Tentatively Selected Plan Identified Properties and Nearby USEPA 303(d) Listed Waterbodies

Reach Parcel ID Structure Type Nearby 303(d) Reach ID Middle Sweetwater Creek

PID_SCe Residence R031300020217

PID_SCf Business R031300020217 Noses Creek PID_NCa Residence R031300020204 PID_NCb Auto Repair R031300020204

Table 30: Tentatively Selected Plan Identified Properties and Likelihood of

Nearby State Waters Reach Parcel ID Structure Type Within/Near Stream Buffer

Zone Upper Sweetwater Creek

PID_SCa Residence No

PID_SCb Residence No PID_SCc Residence No

Middle Sweetwater Creek

PID_SCd Service Station No

PID_SCe Residence No PID_SCf Business No


PID_PCa Residence No

PID_PCb Residence Yes PID_PCc Residence Yes PID_PCd Residence Yes PID_PCe Residence Yes PID_PCf Residence No PID_PCg Residence No

Noses Creek PID_NCa Residence No PID_NCb Auto Repair No PID_NCc Residence No PID_NCd Residence No PID_NCe Residence No PID_NCf Residence No PID_NCg Residence No

49

Groundwater

No seepage would occur as a result of the recommended action therefore no effects to groundwater would occur.

5.5 Biological Resources

Vegetation No activities under the TSP would involve the removal of vegetation. Following demolition and grading of the existing structures, locally sourced native seed may be used to prevent further runoff. Long term benefits may occur as a result of the TSP through establishment of a more natural floodplain. Each location may experience the regrowth of forested habitat after years of vacancy. Therefore the TSP may result in beneficial impacts to vegetation.

Fish and Wildlife Resources Each existing structure identified for demolition currently is inhabited. It is assumed that each structure is devoid of wildlife infestation, such as bats or rodents. Prior to demolition each structure would be inspected. Should inspection show signs of wildlife infestation measures will be taken to safely remove the creatures. The TSP would result in the conversion of residential structures to vacant lots which may benefit local wildlife species in the long term. Years of vacancy may result in a reestablishment of forested habitat suitable for common species within the area. In accordance with Executive Order 13112 Safeguarding the Nation from the Impacts of Invasive Species the areas selected for evacuation/relocation incentives will reseed each site with native species. The further prevention of invasive species growth will be realized through the existing Cobb County property maintenance program once the project is turned over to the non-federal sponsor.

Waters of the U.S. including Wetlands Prior to demolition each parcel identified for buyout will be surveyed by a qualified wetland biologist to delineate any jurisdictional wetlands that may exist within the demolition radius. Demolition crews would be instructed to avoid staging or access activities within delineated wetland areas. Therefore, the TSP would not result in negative impacts to waters of the United States including wetlands.

Special Status Species Endangered Species Act

No impacts to federally-protected species would result from the TSP. No suitable habitat for federally-listed threatened or endangered species exists within the identified parcels for buyout. Therefore no disturbances through a temporary increase in noise levels as a result of demolition activities would affect federally-protected migrant species within each parcel.

50

Migratory Bird Treaty Act The 20 parcels are situated in moderately developed portions of the study area. Any migratory birds inhabiting the 20 parcels would most likely occupy areas of least disturbance. Demolition may result in localized and temporary noise level increases, however these increases would be minor and would revert to pre-demolition levels upon completion. Therefore, the TSP would have little to no effect on any migratory bird within the 20 parcels.

Bald and Golden Eagle Protection Act The TSP would have no effect on bald or golden eagles. Prior to demolition activities, each parcel would be inspected by a qualified wildlife biologist for the presence of bald or golden eagle nests. Demolition of structures within parcels which contain eagle nests will maintain a buffer zone in accordance with the USFWS National Bald Eagle Management Guidelines dated May 2007 and included in Appendix E. No impacts would occur as a result of noise interference. Therefore, the TSP would have no effect on bald or golden eagles within the study area.

Wildlife Corridors The conversion of the structures to vacant lots may benefit wildlife corridors by allowing the regeneration of vegetation throughout each area. Tree regrowth would connect fragmented habitats between the parcels and surrounding habitats. Therefore the TSP may have a beneficial impact to wildlife corridors within the study area.

5.6 Cultural Resources Cultural Resource Identification

The TSP would have no impact on any previously identified cultural resources but their remains the possibility that unknown cultural resources eligible for listing on the NRHP are located within the project area. The USACE, Mobile District proposes to fulfill the requirements of Section 106 of the NRHP and NEPA by conducting a historic architecture survey of all structures to be demolished and archaeological survey of all areas impacted by demolition activities under the TSP. The resulting cultural resources reports will be coordinated with the Georgia State Historic Preservation Officer (SHPO) and any Interested Federally Recognized Indian Tribes. If any cultural resources eligible for listing on the NRHP are identified as a result of these surveys and in consultation with the SHPO and Tribes, an MOA will be developed to mitigate adverse effects to historic properties.

5.7 Sociological Resources

Flooding and Flood Damages The TSP would result in the removal of structures affected by frequent flooding within Cobb County leading to a reduction in the quantity of structures experiencing flood damages. Therefore the TSP would have a beneficial impact on the study area.

51

Hazardous Toxic Radiological Waste The TSP would not result in an increase in HTRW within the 20 parcels. Table 31: TSP Identified Properties and Age of Structures lists the properties with identified RECs and shows the potential for the presence of harmful substances based on the age of each structure.

Table 31: TSP Identified Properties and Age of Structures Reach Parcel ID Structure Type Year Built*

Upper Sweetwater Creek

PID_SCa Residence 1942

PID_SCb Residence 1988 PID_SCc Residence 2002 Middle Sweetwater Creek

PID_SCd Service Station 1945

PID_SCe Residence 1958 PID_SCf Business Unknown


PID_PCa Residence 1959

PID_PCb Residence 1973 PID_PCc Residence 1973 PID_PCd Residence 1973 PID_PCe Residence 1973 PID_PCf Residence 1973 PID_PCg Residence 1984

Noses Creek PID_NCa Residence 1971 PID_NCb Auto Repair 1971 PID_NCc Residence 1993 PID_NCd Residence 1995 PID_NCe Residence 1995 PID_NCf Residence 1997 PID_NCg Residence 1998

*based on tax data Of the 20 properties, two properties with RECs were identified in the initial review. The property within PID_SCd appears to be an abandoned service station which sits adjacent to a former auto salvage business. The concern for such a property would

52

primarily be improperly abandoned underground fuel storage tanks or improperly disposed of waste oil products, which could lead to soil and/or groundwater contamination. Additional assessment is needed to confirm historical property usage, as well as the status of any possible cleanup activities. The property within PID_NCb sits within the Noses Creek reach and appears to house a home auto repair/salvage business on the back/northern portion of the property. This property was not identified by the environmental database search, but was identified during the inspection of potential buyout properties. The concern for this property would primarily be improper disposal of waste oil products. Additional assessment is needed to determine the potential for existence of any contamination. Additional assessment of property within PID_SCf, which appears to be a horse stable, is needed to determine the likelihood of RECs within the stable area. Each site would be further inspected for the presence of HTRW substances prior to implementation through a Supplemental Phase I Environmental Site Assessment to determine if a Phase II HTRW assessment is necessary. Should site inspections reveal contamination, Cobb County would remediate any harmful substances. The USACE would reimburse Cobb County solely for property purchase once an inspection following remediation procedures shows no contamination. The remaining 17 residential structure would be inspected prior to demolition for signs of lead based paint, asbestos, toxic mold, or other harmful substances. Structures built prior to 1980 have a higher likelihood of containing lead based paint, asbestos, toxic mold, or other harmful substances. The removal of harmful substances would be accomplished through State licensed contractors and would abide by USEPA and OSHA requirements. Considering the above mitigation measures, the TSP is likely to have no adverse effects on the environmental as a result of HTRW related substances.

Noise The 20 parcels identified for buyouts within the 10% ACE floodplain identified in Figure 15: are located in low to moderate intensity developed portions of the study area as shown in Figure 4: Sweetwater Creek Watershed National Land Cover Database Overview. These areas experience relatively low to moderate ambient noise levels compared to heavily urbanized cities. Localized and temporary increases in noise levels would occur as a result of demolition equipment and activities. These increases would be minor and would revert to pre-demolition levels upon completion. Therefore, the TSP would have no adverse impacts on ambient noise levels.

Aesthetic Following removal of structures at each parcel, immediate effects of the TSP would result in vacant and barren appearances at each site. Aesthetics would improve upon the establishment of the seeded areas. Long term benefits may occur as the

53

establishment of vegetation changes to a more natural floodplain. Therefore the TSP would result in slightly beneficial improvements.

Navigation No activities would occur within navigable waterways as a result of the TSP. Therefore no effects to navigation would occur.

Socioeconomics Socioeconomics of the study area would experience an increased benefit as a result of the TSP. Homeowners experiencing frequent flooding would benefit from relocation incentives which would provide homeowners with the opportunity to move to less flood prone areas. The entire study area would benefit from local economic stimulus as a result of increased job opportunities for local contractors and businesses as evidenced by the Regional Economic Development model in Appendix A. Therefore there would be an increased benefit as a result of the recommended action.

Public Safety Increased public safety would occur through the buyout of each parcel. Local emergency operatives would benefit because they would not need to visit those parcels experiencing frequent flooding. Relocated homeowners and families would benefit physically and emotionally by moving to less flood prone areas. Therefore the TSP would result in an increased benefit to the study area.

Recreation Because the TSP would not involve activities occurring at or near recreation sites, effects resulting from the TSP would be similar to the Future Without Project Conditions as analyzed in Section 2.7.8 Recreation. Therefore, the TSP would have minor adverse effects, such as temporarily inaccessible recreation facilities, to recreation within the study area. 6.0 Environmental Compliance

Federal laws and Executive Orders applicable to the USACE TSP, their applicability to the proposed project, and, if applicable, their status is presented in Table 32 below:

54

Table 32: Public Law Environmental Compliance Status

STATUS PUBLIC LAW (US CODE)/EXECUTIVE ORDER N/A Abandoned Shipwreck Act of 1987 (43 U.S.C. 2101) N/A American Indian Religious Freedom Act (42 U.S.C. 1996) N/A Agriculture and Food Act (Farmland Protection Policy Act) of 1981 (7 U.S.C. 4201) N/A American Folklife Preservation Act of 1976, As Amended (20 U.S.C. 2101) N/A Anadromous Fish Conservation Act of 1965, As Amended (16 U.S.C. 757a et seq) N/A Antiquities Act of 1906, As Amended (16 U.S.C. 431) C Archeological and Historic Preservation Act of 1974, As Amended (16 U.S.C. 469) N/A Archeological Resources Protection Act of 1979, As Amended (16 U.S.C. 470) N/A Bald Eagle Act of 1972 (16U.S.C. 668) N/A Buy American Act (41 U.S.C. 102) N/A Civil Rights Act of 1964 (Public Law 88-352) (6 U.S.C. 601) C Clean Air Act of 1972, As Amended (42 U.S.C. 7401 et seq) C Clean Water Act of 1972, As Amended (33 U.S.C. 1251 et seq) N/A Barrier Resources Act of 1982 (16 U.S.C. 3501-3510) N/A Coastal Zone Management Act of 1972, As Amended (16 U.S.C. 1451 et seq) N/A CERCLA of 1980 (42 U.S.C. 9601) N/A Conservation of Forest Lands Act of 1960 (16 U.S.C. 580 mn) N/A Contract Work Hours (40 U.S.C. 327) N/A Convict Labor (18 U.S.C. 4082) N/A Copeland Anti-Kickback (40 U.S.C. 276c) N/A Davis-Bacon Act (40 U.S.C. 276) N/A Deepwater Port Act of 1974, As Amended (33 U.S.C. 1501) N/A Emergency Flood Control Funds Act of 1955, As Amended (33 U.S.C. 701m) N/A Emergency Wetlands Resources Act (16 U.S.C. 3901-3932) C Endangered Species Act of 1972 (16 U.S.C. 1531) C EO 11988, Floodplain Management C EO 11990, Protection of Wetlands C EO 12898, Environmental Justice N/A Estuary Protection Act of 1968 (16 U.S.C. 1221 et seq) N/A Equal Opportunity (42 U.S.C. 2000d) N/A Farmland Protection Policy Act (7 U.S.C. 4201 et seq) N/A Federal Environmental Pesticide Act of 1972 (7 U.S.C. 136 et seq) N/A Federal Water Project Recreation Act of 1965, As Amended (16 U.S.C. 4601) P Fish and Wildlife Coordination Act of 1958, As Amended (16 U.S.C. 661) N/A Flood Control Act of 1944, As Amended, Section 4 (16 U.S.C. 460b) N/A Food Security Act of 1985 (Swampbuster) (16 U.S.C. 3811 et seq) N/A Hazardous Substance Response Review Act of 1980, As Amended (26 U.S.C.4611) N/A Historic and Archeological Data Preservation (16 U.S.C. 469)

55

STATUS PUBLIC LAW (US CODE)/EXECUTIVE ORDER C Historic Sites Act of 1935 (16 U.S.C. 461) Note: Superseded by NHPA, Section 106 N/A Jones Act (46 U.S.C. 292) N/A Land and Water Conservation Fund Act of 1965 (16 U.S.C. 4601) N/A Magnuson Fishery Conservation and Management Act (16 U.S.C. 1801) N/A Marine Mammal Protection Act of 1972, As Amended (16 U.S.C. 1361) N/A Marine Protection, Research and Sanctuaries Act of 1972 (33 U.S.C. 1401) N/A Migratory Bird Conservation Act of 1928, As Amended (16 U.S.C. 715) C Migratory Bird Treaty Act of 1918, As Amended (16 U.S.C. 703) C NEPA of 1969, As Amended (42 U.S.C. 4321 et seq) C National Historic Preservation Act of 1966, As Amended (16 U.S.C. 470) C National Historic Preservation Act Amendments of 1980 (16 U.S.C. 469a) N/A Native American Religious Freedom Act of 1978 (42 U.S.C. 1996) N/A Native American Graves Protection and Repatriation Act (25 U.S.C. 3001) N/A National Trails System Act (16 U.S.C. 1241) N/A Noise Control Act of 1972, As Amended (42 U.S.C. 4901 et seq) N/A Rehabilitation Act of 1973 (29 U.S.C. 794) N/A Reservoir Salvage Act of 1960, As Amended (16 U.S.C. 469) N/A Resource Conservation and Recovery Act of 1976 (42 U.S.C. 6901-6987) N/A River and Harbor Act of 1888, Section 11 (33 U.S.C. 608) N/A River and Harbor Act of 1899, Sections 9, 10, 13 (33 U.S.C. 401-413) N/A River and Harbor and Flood Control Act of 1962, Section 207 (16 U.S.C. 460) N/A River and Harbor and FC Act of 1970, Sects 122, 209 and 216 (33 U.S.C. 426 et

seq) N/A Safe Drinking Water Act of 1974, As Amended (42 U.S.C. 300f) N/A Shipping Act (46 U.S.C. 883) N/A Submerged Lands Act of 1953 (43 U.S.C. 1301 et seq) N/A Superfund Amendments and Reauthorization Act of 1986 (42 U.S.C. 9601) N/A Surface Mining Control and Reclamation Act of 1977 (30 U.S.C. 1201-1328) N/A Toxic Substances Control Act of 1976 (15 U.S.C. 2601) N/A Policy Act of 1970, As Amended (43 U.S.C. 4601) N/A Utilization of Small Business (15 U.S.C. 631, 644) N/A Wild and Scenic River Act of 1968 (16 U.S.C. 1271 et seq)

Key: N/A = Non-applicable; C = In compliance; P = Compliance pending Assuming that the proposed project does not expand beyond the scope described in this draft report, the TSP is in compliance with NEPA.

6.1 Coordination This feasibility study was coordinated with the USFWS Athens Field Office, Georgia SHPO, and federally recognized tribes. Cooperating agency letters dated December 20, 2017 were mailed to affected state and federal agencies and are included in

56

Appendix F. Electronic correspondence for participation of the USACE TSP Milestone Meeting was submitted to each agency identified in Table 33: Coordination.

Table 33: Coordination Federal State

Department of Interior Georgia Department of Natural Resources Department of Interior Atlanta Region

Georgia Department of Natural Resources Environmental Protection Division

Environmental Protection Agency Region 4

Georgia Department of Natural Resources Wildlife Resources Division

Federal Emergency Management Agency Region 4

Georgia Department of Public Safety

U.S. Fish and Wildlife Service Athens Field Office

Georgia Department of Transportation

U.S. Fish and Wildlife Service Southeast Region

Georgia Emergency Management Agency

U.S. Geological Survey Southeast Region

Georgia Secretary of State

Georgia Soil and Water Conservation Commission

Fish and Wildlife Coordination Act

According to the Water Resources Development Under the Fish and Wildlife Coordination Act (FWCA) report dated November 2004, “The FWCA provides a basic procedural framework for the orderly consideration of fish and wildlife conservation and enhancement measures in federally constructed, permitted, or licensed water development projects. The FWCA provides that, whenever any water body is proposed to be controlled or modified “for any purpose whatever” by a Federal agency or by any “public or private agency” under a Federal permit or license, the action agency is required first to consult with the wildlife agencies, “with a view to the conservation of fish and wildlife resources in connection with that project.” The FWCA authorizes preparation of reports and recommendations by the Secretary of the Interior (and/or Commerce) and the head of the State agency responsible for the administration of fish and wildlife resources, to be submitted to the action agency. That report, if prepared, must be made available to the Congress or other authorizing agents when decisions are made to authorize (or not to authorize, or authorize with modifications) a project. Other provisions of the FWCA relate to the acquisition and use of project lands and waters for fish and wildlife purposes, the evaluation of project effects including benefits and costs, and related matters.” The Sweetwater Creek FRM feasibility study is considered a federal project for the purpose of evaluating the manipulation of a body of water. The USACE coordinated closely with the USFWS Athens Field Office regarding the study and subsequent development of the Fish and Wildlife Coordination Act Report, Appendix F. 7.0 References

Alain Vauchez; Brevard fault zone, southern Appalachians: A medium-angle, dextral, Alleghanian shear zone. Geology; 15 (7): 669–672. July 01, 1987. doi: <https://doi.org/10.1130/0091-7613(1987)15<669:BFZSAA>2.0.CO;2>.

57

Bailey, Robert G. 2016. Bailey's ecoregions and subregions of the United States, Puerto

Rico, and the U.S. Virgin Islands. Fort Collins, CO: Forest Service Research Data Archive. <https://doi.org/10.2737/RDS-2016-0003>.

Bailey, Robert G., compiler. 1995. Description of the Ecoregions of the United States.

2d ed. rev. and expanded (1st ed. 1980). Misc. Publ. No. 1391 (rev.), Washington, DC: USDA, Forest Service. 108 p. with separate map at 1:7,500,000. Also online reference, USDA Forest Service, Ft. Collins, CO. Available: http://www.fs.fed.us/land/ecosysmgmt/ecoreg1_home.

Cobb County Government. Cobb County Water System Stream Monitoring. Obtained

23 February 2018. <https://cobbcounty.org/index.php?option=com_content&view=article&id=2349&Itemid=1327>

Cowardin, Lewis M., Carter, Virginia, Golet, Francis C., LaRoe, Edward T. U.S.

Department of the Interior Fish and Wildlife Service. Biological Services Program FWS/OBS-79/31. Classification of Wetlands and Deepwater Habitats of the United States. December 1979. Reprinted 1992

Environmental Protection Agency. 1999. Primary Distinguishing Characteristics of Level

III Ecoregions of the Continental United States. EPA Site: http://www.epa.gov/wed/pages/ecoregions/level_iii.htm. Accessed February 10, 2018.

Erwin, K.L. (2009) Wetlands and Global Climate Change: The Role of Wetland

Restoration in a Changing World. Wetlands Ecology and Management, 17, 71-84. <http://dx.doi.org/10.1007/s11273-008-9119-1>.

Federal Geographic Data Committee. 2013. Classification of wetlands and deepwater

habitats of the United States. FGDC-STD-004-2013. Second Edition. Wetlands Subcommittee, Federal Geographic Data Committee and U.S. Fish and Wildlife Service, Washington, DC.

Garssen, Annemarie G., Baattrup‐Pedersen Annette, Riis Tenna, et al. Effects of

increased flooding on riparian vegetation: Field experiments simulating climate change along five European lowland streams. Glob Change Biol. 2017;23:3052–3063.<https://doi.org/10.1111/gcb.13687>.

Georgia Environmental Protection Division Watershed Protection Branch. HR 1198

Review of Regulations Related to Aquifer Storage and Recovery. 7/11/2017. <https://epd.georgia.gov/sites/epd.georgia.gov/files/related_files/site_page/HR1111_Public_Review_Draft_Report.pdf>.

58

Georgia Department of Natural Resources, Environmental Protection Division. “Draft 2016 Integrated 305(b)/303(d) List - Streams.” Draft 2016 Integrated 305(b)/303(d) List - Streams, 15 Sept. 2016. <epd.georgia.gov/sites/epd.georgia.gov/files/related_files/site_page/303d_Draft_Streams_Y2016.pdf>.

Georgia Department of Natural Resources, Environmental Protection Division.

Geographic Information Systems GIS Databases and Documentation. 20 March 2018. <https://epd.georgia.gov/geographic-information-systems-gis-databases-and-documentation>.

Georgia Department of Natural Resources State Parks and Historic Sites personal

communication 2/9/2018 Georgia Department of Natural Resources Wildlife Resources Division. Aug. 2001.

Georgia Ecoregions: Maps & Descriptions. <georgiawildlife.com/georgia-ecoregions-maps-and-descriptions>.

Google Earth Pro. Sweetwater Creek Study Area 10% Chance of Exceedance

Floodplain Overview. USACE 10% Chance of Exceedance Floodplain data layer, viewed 29 January 2018. <https://www.google.com/earth/desktop/>.

Google Earth Pro. Sweetwater Creek Study Area Land Use Overview. Multi-Resolution

Land Characteristics Consortium National Land Cover Database 2011 data layer, viewed 2 February 2018. <https://www.mrlc.gov/arcgis/rest/services/LandCover/USGS_EROS_LandCover_NLCD/MapServer/export>. <https://www.google.com/earth/desktop/>.

Google Earth Pro. Sweetwater Creek Study Area USEPA Ecoregion Overview. USEPA

Ecoregions Level III and Level IV data layer, viewed 8 February 2018. <https://geodata.epa.gov/arcgis/services/ORD/USEPA_Ecoregions_Level_III_ana_IV/MapServer/KmlServer?Composite=false&VectorsToRasters=true&LayerIDs=1%2C8>. <https://www.google.com/earth/desktop/>.

Google Earth Pro. Sweetwater Creek Study Area Wetlands Overview. FWS Wetlands &

Riparian data layer, viewed 10 January 2018. <http://www.fws.gov/wetlands/Data/Google-Earth.html>. <https://www.google.com/earth/desktop/>.

Homer, C.G., Dewitz, J.A., Yang, L., Jin, S., Danielson, P., Xian, G., Coulston, J.,

Herold, N.D., Wickham, J.D., and Megown, K., 2015, Completion of the 2011 National Land Cover Database for the conterminous United States-Representing a decade of land cover change information. Photogrammetric Engineering and Remote Sensing, v. 81, no. 5, p. 345-354.

59

Information for Planning and Consultation, U.S. Fish & Wildlife Service, accessed 2 February 2018 <ecos.fws.gov/ipac/location/6FD7HUO2RNGYTA2ZIQNYDGN4L4/resources>.

Mayer et. al. U.S. Environmental Protection Agency. Riparian Buffer Width, Vegetative

Cover, and Nitrogen Removal Effectiveness: A Review of Current Science and Regulations. EPA/600/R-05/118. October 2005.

Omernik, J.M. 1987. Ecoregions of the conterminous United States. Map (scale

1:7,500,000). Annals of the Association of American Geographers 77(1):118-125. Peck, M.F., Leeth, D.C., and Painter, J.A., 2011, Groundwater conditions and studies in

Georgia, 2008–2009; U.S. Geological Survey Scientific Investigations Report 2011–5048, 83 p.

Sukenick, Adam. Personal Communications. Sweetwater Data/Cobb County. 7

November 2017. The White House. Office of the Press Secretary. December 05, 2016. Executive Order -

- Safeguarding the Nation from the Impacts of Invasive Species. U.S. Army Corps of Engineers. (2000). ER 1105-2-100: Planning Guidance Notebook. U.S. Army Corps of Engineers. (2012). EC 1165-2-214: Water Resources Policies and

Authorities Civil Works Review U.S. Army Corps of Engineers. (2016). ECB 2016-25: Guidance for Incorporating

Climate Change Impacts to Inland Hydrology in Civil Works Studies, Designs, and Projects.

U.S. Army Corps of Engineers. (2017). ER 1105-2-101: Risk Assessment for Flood Risk

Management Studies U.S. Department of Agriculture Soil Conservation Service. 1981. Land resource regions

and major land resource areas of the United States. (Agr. Handb. 296 (rev.).) Washington, DC: U.S. Department of Agriculture. 427-428 p.

U.S. Department of the Interior. U.S. Geological Survey. Michael W. Higgins, Thomas J.

Crawford, Robert L. Atkins, Ralph F. Crawford. Geologic Map of the Atlanta 30' x 60' Quadrangle, Georgia. Geologic Investigations Series Map 1-2602. 2003 <https://pubs.usgs.gov/imap/2602/report.pdf>.

U.S. Fish and Wildlife Service. Endangered Species Act Overview. 1 November 2017.

Endangered Species. <https://www.fws.gov/endangered/laws-policies/>.

60

Western Geographic Science Center. “Land Cover Trends.” Land Cover Change, <landcovertrends.usgs.gov/east/eco45Report.html>.